Answer:
2
Step-by-step explanation:
18-20=2 so thats your answer
x^2 + 2x + 1 = 17
x^2 + 2x = 17 - 1
x^2 + 2x = 16
x^2 + 2x + 1 = 16 + 1
(x + 1)(x + 1) = 17
(x + 1)^2 = 17
x + 1 = sqrt 17
x = -1 (+ - ) sqrt 17
x = -1 + sqrt 17 or x = -1 - sqrt 17 <===