Question

Find the zeros of y = x2 - 4x - 9 by completing the square.

ОА. x = -2 + 13
OB. х = 3+ (113
ос. х = 2+ (13
OD. х = +3

Answer 1

`{x}^(2) - 4x - 9 = 0 \\ d = {( - 4)}^(2) - 4 * ( - 9) = 52 = (2 √(13) ) ^(2) \\ x = (4 + 2 √(13) )/(2) = 2 + √(13) \\ x = (4 - 2 √(13) )/(2) = 2 - √(13)`

Zeros of function:

2+_/13

2-_/13