Eight times the sum of a number and one is -8

X= a number
times= multiply
sum= add

8(x + 1)= -8
multiply 8 by parentheses

(8*x) + (8*1)= -8

8x + 8= -8
subtract 8 from both sides

8x= -16
divide both sides by 8

x= -2

CHECK:
8(x + 1)= -8
8(-2 + 1)= -8
8(-1)= -8
-8= -8

ANSWER: The number is -2.

Hope this helps! :)