Question

If a(z) = 2z - 7, then a(?) = 2(x+1) -7

Answer 1

If a(z) = 2z - 7, then a(x+1) = 2(x+1) -7

Answer 2

In a(z) = 2z -7, the variable z is in place of x.

So a(?) would be a(x+1) because instead of z there is x + 1