What’s the range of y= -x2- 4x +12

Question

Im not quit sure how to find the range and need a wee bit of help

Answer 1

y = -x² - 4x + 12

y = -(x² + 4x    ) + 12

y = -(x² + 4x + 4) + 12 + 4

y = -(x + 2)² + 16

 

Range = {y | y ≤ 16}