Question

Evaluate the function y = 17 – x. when x = –6

Answer 1

y=17-(-6) changes the equation to y=17+6 (since two negatives make a positive) and make the answer 23

Answer 2

Evaluate just means solve it. If x is -6, that just means put -6 in for x and solve.
y=17 - -6. Subtracting a negative is the same as adding a positive, so it's the same as y=17 + 6, which is y=23.