0
We have the following quadratic equation:
y= x2 + 8x + 15
We need to find the x-intercepts of the equation, or the points where the equation equals zero. To do this, we can factor the equation. Take the following equation:
y = (x + a)(x + b)
We can factor the equation into this form, if we can find numbers a and b such that:
a + b = 8
a * b = 15
After some trial and error, we find that a = 3 and b = 5.
x2 + 8x + 15 = (x + 3)(x + 5)
If either part of the factored form is equal to zero, the entire equation is equal to zero. The points where this is true are at x = -3 and x = -5. Therefore, the answers are
x = -3 and x = -5.
Still curious? Ask our experts.
Chat with our AI personalities
Judy
Vivi
CoachAdd your answer:
Earn +20 pts
How do you factor x2 plus 8x plus 15?
x2 + 8x + 15 = (x + 3) (x + 5).
Factor X2 plus 8x equals -15?
x2 + 8x = -15 x2 + 8x + 15 = 0 since 15 = 5 x 3 and 5 + 3 = 8, then (x + 5)(x + 3) = 0 x + 5 = 0 or x + 3 = 0 x = -5 or x = -3
Vertex of x2 plus 8x plus 15?
(-4,-1)
X2 plus 8x plus 9 equals -7?
x2+8x+9 = -7 x2+8x+9+7 = 0 x2+8x+16 = 0 (x+4)(x+4) = 0 Therefore: x = -4 and also x = -4 (they both have equal roots)
X2 plus 8x-6 equals 0?
x2 + 8x - 6 = 0 x2 + 8x + 16 = 22 (x + 4)2 = 22 x + 4 = ± √22 x = -4 ± √22
