If y=x^2+8x+9, what's the 2 x-intercepts of the parabola?

x = - 4 ±√ (7)

or in decimal:

x = - 1.35 or - 6.65

Step-by-step explanation:

y=x²+8x+9

note x-intercepts occur when y = 0,

Hence, x²+8x+9 = 0 (solve this using your favorite method. We will complete the square)

x²+8x+9 = 0 (rearrange)

x²+8x = - 9 (complete the square and add factor to both sides)

x² + 8x + (8/2) ² = - 9 + (8/2) ²

[ x + (8/2) ]² = - 9 + (8/2) ²

[ x + 4 ]² = - 9 + (4) ²

[ x + 4 ]² = - 9 + 16

[ x + 4 ]² = 7

x+4 = ±√ (7)

x = - 4 ±√ (7)

x = - 1.35 or - 6.65