Question #72d7d

1 Answer

x=-3±sqrt14

Explanation:

Find two numbers that multiply to negative 5 and add to 6.

Since 5 is a prime number, its only factors are 5 and 1.

If one of these is negative then they'll multiply to -5. Unfortunately, -5 xx 1 = 5 but -5+1=-4 and not 6

Also 5 and -1 add to 4 and not 6... this means it can't be factorised so we will have to use completing the square or the quadratic formula.

First, divide 6 by two and square it with x:

(x+3)^2 this would expand to x^2+6x+9 which is right except for the 9 - we need -5 so we subtract 14.

(x+3)^2-14=0

now solve for x:
(x+3)^2=14
x+3=±sqrt14
x=-3±sqrt14