Step-by-step explanation:
[tex]9x - 3 - 20 + 8x = - 10 \\ 17x - 23 = - 10 \\ 17x = - 10 + 23 \\ 17x = 13 \\ \frac{17x}{17} = \frac{13}{17} \\ x = \frac{13}{17} [/tex]