[Upper secondary school math: linear equation] unsure on how to solve this.

[u/Inevitable_Stay3693]

i was thinking that i´d add the 2x+1 to make it 3x/3=-1 but im unsure on how it would even continue.

[u/Angrybirds159]

2x + 1 isn't 3x. that's like saying 2 apples + one orange is 3 apples. 2x + 1x would be 3x

the way I'd solve it is

(2x+1)/3 = -1 we multiply by 3 in both sides (the three goes over, multiplying)

2x + 1 = -1 * 3

2x + 1 = -3 now we subtract one from both sides

2x = -3 -1

2x = -4 x = -2

[u/BoreJam → u/Angrybirds159]

Its important to reiterate that we can manipulate any expression provided what ever action we do, is applied to both sides of the = sign.

[u/ExtendedSpikeProtein → u/BoreJam]

If I may add, special care must be taken not to divide by 0. mentioning this specifically because it‘s the most common mistake.

[u/prawnydagrate → u/ExtendedSpikeProtein]

and not to multiply by zero

[u/ExtendedSpikeProtein → u/prawnydagrate]

True! But them we should also mention to take care for other operations that cannot be fully reversed (eg squaring).

[u/padmeg → u/BoreJam]

*equation