Equation
Let the number = x
2*(x + 9) = x - 8
Solve
2(x + 9) = x - 8 Remove the brackets on the left
2x + 18 = x - 8 Subtract x from both sides
2x - x + 18 = - 8 2x and - x will combine
x + 18 = - 8 Subtract 18 from both sides
x = -8 - 18
x = - 26
Check
LHS
2(-26 + 9)
2(-17)
-34
RHS
x - 8
-26 - 8
- 34 and the RHS = LHS and they check
Your number would be -26
Sorry if this is wrong but I'm pretty sure its right
