How do you solve -8x = - 21- 9x?

2 Answers
Apr 26, 2018

x=-21

Explanation:

"collect terms in x on the left side of the equation"
"and numeric values on the right side"

"add 9x to both sides"

-8x+9x=-21cancel(-9x)cancel(+9x)

rArrx=-21

color(blue)"As a check"

Substitute this value into the equation and if both sides are equal then it is the solution.

"left "=-8xx-21=168

"right "=-21+(-9xx-21)=-21+189=168

rArrx=-21" is the solution"

Apr 26, 2018

x=-21

Explanation:

-8x=-21-9x

We need to put every expression with x on the left side of the equals sign and the number on the right.

-8x+9x=-21

x=-21