equation

Solve for x:
(x+11)/10 = -2 (8-x)

Multiply both sides by 10:
(10 (x+11))/10 = -2×10 (8-x)

(10 (x+11))/10 = 10/10×(x+11) = x+11:
x+11 = -2×10 (8-x)

10 (-2)  =  -20:
Answer: | 
| x+11 = -20 (8-x)                    x=9