Question

Which equation has a solution of -2?

A 7x - 4 = 6x + 5
B 4x + 3 = 8x - 5
C 6x + 4 = 3x + 10
D -5x - 3 = -7(x +1)

Answer 1

I'm not sure if there is law for it or not, but you can replace each x to -2 if both sides are equal then the equation is true.

`7x - 4 = 6x + 5\\7(-2) - 4 = 6(-2) + 5\\-14-4=-12+5\\-18\\eq -7`

A. is incorrect.

`4x + 3 = 8x - 5\\4(-2) + 3 = 8(-2) - 5\\-8+3=-16-5\\-5\\eq -21`

B. is incorrect.

`6x + 4 = 3x + 10\\6(-2) + 4 = 3(-2) + 10\\-12+4=-6+10\\-8\\eq 4`

C. is incorrect.

`-5x - 3 = -7(x +1)\\-5(-2) - 3 = -7((-2) +1)\\10-3 =-7(-1)\\7=7`

D. is correct.

Answer:

D.
`-5x-3=-7(x+1)`

Hope this was helpful.