Question

Find the x-intercepts for the parabola defined by this equation:
y=-2x^2-4x+6
Write your answer as two ordered pairs:
(x1,y1),(x2,y2)
Separate the values with a comma. Round, if necessary, to the nearest hundredth.

@lucaz

Answer 1

factor out -2
-2(x^2+2x-3)
an easy way to factor quadratics is this
Ax^2+Bx+C=0, where A=1, B=2 and C=-3
now find two numbers a and b that the product is A*C and the sum is B, then the factored form will be (x+a)(x+b)
A*C=1*-3=-3 and B=2
try the numbers 3 and -1
3*-1=-3 and 3+(-1)=2, they work, so the factored form is (x+3)(x-1).
then you have -2((x+3)(x-1))=0
x+3=0 -> x=-3
x-1=0 -> x=1
the x-intercepts are (-3,0) and (1,0)
but there are some quadratic equations that cannot be factored, then you will have to use the quadractic formula: