x = - 7
multiply both sides by (x - 10) to eliminate the fraction
391 = - 23(x - 10 ) ← ( distribute parenthesis )
391 = - 23x + 230 ← ( subtract 230 from both sides )
161 = - 23x ← ( divide both sides by - 23 )
[tex]\frac{161}{- 23}[/tex] = x
- 7 = x ⇒ x = - 7