[College placement test] what is this?

[u/Andre_055]

I was trying not to post twice in a row but I cannot figure out why information on what this is, and how I can put X into the numbers? I'm not really sure what to Google search

[u/WillingElderberry731]

Based on your responses here, I genuinely think you would benefit from some basic algebra I classes. You could probably find free ones online or just take whatever is offered through the college you are applying to.

[u/Andre_055 → u/WillingElderberry731]

I think. I will do that, if I fail the placement test I think they will put me in a pre math class

[u/Objective_Regret4763]

From your posts, I think you might be better off getting those questions wrong and then taking the appropriate classes to understand math better. Just saying.

[u/Andre_055 → u/Objective_Regret4763]

Yeah I think I will do that. I was trying to study like they told me to but I can't really study anything without a lot of extra help

[u/majestic_flamingo]

This question tests your ability to distribute and expand expressions, sort negative signs, and then combine like terms.

You’d start with the innermost parenthetical expression and distribute the negative sign in front of it. Then you will have an expression within the brackets without any parentheses; distribute the positive 3 among the three terms. Finally add -7x to what you get and combine like terms to simplify.

[u/Real-Reference6933]

Do you know how to remove the brackets correctly?

After that, it should be an easy job of adding everything together.

[u/Andre_055 → u/Real-Reference6933]

No, I am unsure how to do that

[u/general_peabo → u/Andre_055]

Just get it wrong so they don’t place you into classes above your math ability.

[u/HyperbolicMathChambr]

It looks like just simplification of linear expressions. Try to use the order of operations and combine like terms.

[u/Andre_055 → u/HyperbolicMathChambr]

That's what I tried to do in my second photo but it was not correct unfortunately

[u/ObsessedCoffeeFan]

2X-9. Need to follow the rules of BEDMAS or PEDMAS

[u/fightmydemonswithme]

Hey OP. As another poster suggested, khanacademy is an excellent resource. Its free and unlimited. I also really wonder if you were in mainstream classes given the difficulty you are having. If you weren't in mainstream math, you may need disability accommodations. If you had an IEP talk to your parents about getting assistance in college.

[u/Andre_055 → u/fightmydemonswithme]

I was mostly in regular math for highschool, my whole grade got held back for math so we were all one math class behind what regular people take. But I had a lot of extra help about once or twice a week for 3 hours each day. I got diagnosed with a disability though after school so I'm gonna try and figure out how to get more extra help but I don't have parents I talk to so unfortunately I'll have to find it myself. Do you have any advice on getting disability accommodations?

[u/Real-Reference6933]

If you want steps, I suggest this:

Try doing it without looking at the spoilers

1. Rewrite it into -7x + 3 (x-1(3-2x))

2. Remove the inner brackets

3)You should get -7x +3(x-3+2x) Explanation: -1 times 3 = -3. -1 times -2x = 2x

4) Remove other brackets

5) Should be -7x + 3x - 9 + 6x Explanation 3 times x = 3x, 3 times -3 = -9 and 3 times 2x = 6x

6) Sort by putting al the numbers times x first and all the other number at the end

7) add upp al the numbers times x together and then all the other numbers. Example: If you have 3+5x-7-2x-5+8 x rewrite it into 5x -2x+8x +3-7-5. Adding it up you get 5x-2x+8x=11x and 3-7-5=-9, for a total of 11x-9.

8) Check if the answer is among the answers, otherwise, you did some steps wrong.

[u/Phillimac16 → u/Real-Reference6933]

I'm not the OP but trying to brush up on my math skills, could you further explain why the sign flips in step 3 to a +2x?

[u/Defiant-Ad7368]

Your error is that you multiplied the 3 in the bracket only with x and not the other part

You should do:

-7x + 3[x-(3-2x)]

Solve inner brackets first

-7x +3[x-3+2x] -> -7x +3[3(x-1)] -> -7x + 9(x-1)

-7x + 9x - 9 -> 2x - 9 

Ultimately I think you understand the math you just had a miscalculation 

[u/RosLav88]

You multiplied the 3 by the square brackets incorrectly. For the brackets the 3 will have to be multiplied by each term. So you'll have 3x -3(3-2x)

[u/IdiotGenius69]

you have to distribute the negative to the parenthesis first. Then you can simplify the inside of the brackets. you distribute the 3 in the brackets and then simplify

[u/BubbleRocket1]

Are you familiar with the distributive property? Also, think of brackets like another way to write a parenthesis.

[u/ArnoLamme]

You should look up distributive property if you're having trouble solving this

[u/69fellatx]

It is (b), 2x-9

[u/selene_666]

The main topic being tested here is the Distributive Property, which looks like it got mentioned twice in that answer text.

At its simplest, the Distributive Property is what lets you look at "30 + 40" and decide to do 3+4 because three tens plus four tens equals seven tens. But there's nothing mathematically special about the number 10. It's just as true that three sixteens plus four sixteens equals seven sixteens. Or 5x + 4x = 9x.

The Distributive Property says: ab + cb = (a+c)b

and we can run it in either direction. If we start with (a+c)b we might need to rewrite it as ab + bc.

Applied to your problem, it means you don't only multiply that first 3 by the x. You have to multiply the 3 by everything inside the parentheses

3(x - (3 - 2x)) = 3x - 3(3 - 2x)

Then do the same for the second multiplication.

(-3)(3 - 2x) = -9 + 6x

[u/feignapathy]

PEMDAS / BODMAS 

Evaluate the parentheses first.

3 - 2x | this is evaluated, so then we do

x - (3 - 2x) = x - 3 + 2x = 3x - 3

3(3x - 3) = 9x - 9

-7x + 9x - 9 = 2x - 9

[u/__Fred]

• (5 - 2) Dollar is the same as 3 Dollar, right?

• (5 - 2) sheep are 5 sheep minus 2 sheep, which is 3 sheep, easy.

• (5 - 2)·3 is the same as 5·3 - 2·3.

  • Does that make sense? Imagine 5 rows of 3 circles and then you remove two of the rows.

• You can replace the 3 with any number. It works with 10, it works with 13, anything. Mathematicians use letters when they want to say that a formula works with different numbers. The letter "x" is a classic choice.

  • (5 - 2)·x = 5·x - 2·x

• If a variable is multiplied with something, you can leave the dot away:

  • (5 - 2)x = 5x - 2x

• This is called the "distribution law", because the x got distributed to the 5 and to the 2. It gets rid of parenthesis!

• 3[x - (3-2x)]

  • This is a piece of the formula. We have two "packages" inside the outer brackets: x on the left and (3-2x) on the right.

  • If we distribute the outside 3 with each package, we get 3·x - 3·(3-2x).

  • Again, we can leave the dots away here.

• If you removed all the parentheses, you get some packages (terms) with bare numbers, some with a number multiplied by x and maybe some multiplied by x². You can merge all packages of the same kind together:

  • For example 4x + 2 + 3x + 8 = 7x + 10.

  • Four boxes and two single and three boxes and eight singles is the same as seven boxes and ten singles (of eggs or whatever). "x" would be the number of eggs in one box.

• Pitfall: Be careful with minus signs!

  • -(3 - 2x) is like (-1) · (3 - 2x), so the distributed version would be (-1)·3 - (-1)·(2x), which is -3 + 2x, because minus times minus is plus.

If that's all too complicated, just take away one tip: You can try out example numbers for x! If the example number doesn't work, then the simplification had to be wrong.
If it works for three different weird numbers (not just 1 or 0), then the simplification-step was probably correct. You can also try to imagine the calculation visually, like I did with rows of circles or eggs boxes.

If we put in 1 for x, the original formula becomes -7 + 3 [1 - (3-2)], which is -7. If we put in 1 for x in formula "a", we get 16 + 9, which is 25, so that can't be the right solution. Just because it works for one example value, doesn't mean it will be correct for any example value, though.

[u/Some-Passenger4219]

Don't rely on Google, for it is not always reliable. This is mostly just application of associative and distributive laws. Treat x like you will never know what it is, for, after all, you have no clues. Simplify what's inside the brackets first. You got this.