-9x+15=3(2-x)
-9x+15=6-3x
-9x+9=-3
my answer key is tellng me 9 should become negative, why?
-6x-9
x= −9−6or−32 but im still confused on why 9 becomes negative
-9x + 15 = 3(2-x)
Distribute => -9x + 15 = 6 - 3x
Add 9x to both sides => 15 = 6 + (-3 + 9)x
Subtract 6 and distribute => 9 = 6x
x = 3/2
If you subtract 15 from both sides, yes you get -9 because 6 - 15 = -9, but if you subtract 6 from both sides, you get positive 9 on the other side. Combining like terms can give negative numbers.