young solves the equation -2z - 7 = -19 and gets z = 6 which answer best shows how he checked his answer

Answer 1

One possible way Young could have checked his answer is by substituting z = 6 back into the original equation and seeing if it holds true.

-2(6) - 7 = -19
-12 - 7 = -19
-19 = -19

Since both sides of the equation are equal, Young's answer of z = 6 is correct.