Question

Evaluate:
y = x – 13 when x = –3.

Answer 1

y=-3-13 y=-16 you add -3 to -13 to get -16

Answer 2

y = x - 13
x = -3

Since the value of x has already been given, we can substitute its value to the x in the 1st equation.

y = x - 13
   = -3 - 13  *both carry the same negative signs, so addition is                                    performed but the sign is carried over to its sum
y = -16      

(-3,-16)