Question

Solve the equation 3(x-7)-x=2x-21

Answer 1

3(x - 7) - x = 2x - 21
Distribute the the 3: 3x - 7 -x = 2x - 21
Add like terms: 4x - 7 = 2x - 21
Subtract 2x on both sides: 2x - 7 = -21
Add -7 to both sides: 2x = -28

x = -14

Answer 2

first, distribute
3(x-7)=3x-21

3x-21-x=2x-21
3x-1x-21=2x-21
add like terms
2x-21=2x-21
minus 2x oth sides
-21=-21
true

we see that the x's wil cancel

therfor x=all real numbers