Question

Am I doing this wrong?
so for the equation 5x - 8 = 2x + 7,
the school shows me this:
5x - 8 = 2x + 7
5x + -8 = 2x + 7
5x - 2x + -8 = 2x - 2x + 7
3x + -8 = 7
3x + -8 + 8 = 7 + 8
3x = 15
x = 5
But I do it like this:
5x - 8 = 2x + 7
5x - 8 + 8 = 2x + 7 + 8
5x = 2x + 15
5x - 2x = 2x -2x + 15
3x = 15
x =5
Am I doing it wrong?

Answer 1

Nope, that looks correct to me.

Answer 2

You are doing it correctly.
When you have a negative on one side you need to add to get rid of it. If it is a positive then you subtract on both sides.

You answer is then x = 5

Answer 3

While you are not doing it exactly like the school showed you, you are doing it correctly and as you can see obtained the same solution.

Answer 4

In fact, I like your method better, it was more efficient.

Answer 5

Thanks all of you!