Explicación paso a paso:
[tex]a)10 - x = 15 \\ - x = 15 - 10 \\ - x = 5 \\ x = \frac{5}{ - 1} \\ x = - 5 \\ \\ b)x + ( - 8) = 1 \\ x - 8 = 1 \\ x = 1 + 8 \\ x = 9[/tex]
