Question

a). 10x(x+7)-23=177
b).(621-x)x5=495

Answer 1

$\displaystyle a). 10 \times (x+7)-23=177 \\ 10x+70-23=177 \\ 10x=177-70+23 \\ 10x=130 \\ x= \frac{130}{10} \\ \boxed{x=13} \\ b).(621-x) \times 5=495 \\ 3105-5x=495 \\ -5x=495-3105 \\ -5x=-2610 \\ x= \frac{-2610}{-5} \\ \boxed{x=522}$