Answer:
x= 0.25, or x=1/4
Step-by-step explanation:
First, use the distributive property and multiply 7 within the parenthesis:
7x -21
Next, use the distributive property again, and multiply 3 within the parenthesis:
12 -3x
Combine Like terms: 7x - 21 + 12 - 3x
4x - 9
Add 9 to both sides: 4x - 9 = -8
-8 + 9 = 1
Divide 4 by both sides: 4x = 1
1 / 4 = .25 or 1/4
