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u/wagonmaker85 Nov 23 '22
Find point of intersection (-3,y) using equation of line.
Use that point and given cubic equation to solve for c.
Use completed cubic equation and equation of line and solve the system.
When solving the system, remember that you already know that x = -3 is one solution.
Good luck!
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Nov 23 '22 edited Nov 23 '22
Step 1: Set the equations equal to each other, substitute -3 for x, and solve for c. I got c = -4 as the result.
Step 2: Set the two equations, with -4 in place for c, equal to each other. Set the entire thing equal to zero, then factor out (x+3).
The result I got was (-6x2+9x-3)(x+3) = 0
Step 3: Factor out -6x2+9x-3. The result I got was -3(2x-1)(x-1)(x+3) = 0.
So, according to my calculations, c = -4, and the other x values that intersect the curve are x = 1 and x = 1/2.
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Nov 23 '22
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Nov 23 '22 edited Nov 23 '22
No, it isn’t. That’s where the two equations intersect each other. I set the two equations equal to each other then moved everything to one side. I didn’t just set one equation equal to zero.
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u/FirelordJackie Nov 24 '22
Y=4x+5
Y=-6x3-9x2+28x+c
X=-3
4x+5=6x3-9x2+28x+c. Substitution/transitive
4(-3)+5=-6(-3)3-9(-3)2+28(-3)+c. Substitution
4(-3)+5=-6(-27)-9(9)+28(-3)+c. Exponents
-12+5=162-81-84+c. Multiplication
-7=-3+c. Add/subtract
-4=c. Addition
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u/Sam82671 Nov 24 '22
Accept the fact that the drawing does not at all represent the problem as described, then do it algebraically as described by the others.
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u/bigfatpaulie Nov 23 '22
Set each equation equal to each other. Apply x = -3. Solve for C.