15 equals -x plus 8 what is the value of x?

Answer 1

23

Answer 2

If 15=-x+8,
then we use the additive property of equality to see that
-x=15-8.
So after subtracting we have
-x=7 or x=-7.

It is always important to check your answer.

15=-(-7)+8
or 15=7+8 which is true.