Question

Solve x2 + 18x - 40 = 0.

Answer 1

first factor the trinomial
it will be of the form
(x - a)(x + b) where a and b are constants
to find a and b:
you need two numbers whose product is -40 and whose sum is + 18

Answer 2

have you had experience of factoring these?

Answer 3

no I don't get it at all

Answer 4

ok
the 2 numbers are + 20 and -2
20*-2 = -40 and 20 - 2 = 18
so we have
(x + 20)( x - 2) = 0

when 2 items are multiplied together to give zero either one of them must equal zero
so
either x + 20 = 0 or x - 2 = 0

that gives x = -20 or x = 2

solution is -20, 2

Answer 5

hope this helps

Answer 6

thanks alot

Answer 7

yw