Question

Which equation has the same solutions as 2x^2+16x-10=0 a) (x+4)^2=-3 b) (x+4)^2=-11 c) (x+4)^2=13 d) (x+4)^2=21

Answer 1

d) (x+4)² = 21

Explanation:

2x² + 16x - 10 = 0

x² + 8x - 5 = 0

Applying the method of completing the square

x+ 8x + (½×8)² - (½×8)² - 5 = 0

x² + 8x + (4)² - (4)² - 5 = 0

(x + 4)² -16 -5 = 0

(x + 4)² -21 = 0

(x + 4)² = 21