Question

Factor the following problem completely. First, factor out the greatest common factor, and then factor the remaining trinomial:

2y^4 − 4y^3 − 30y^2

Answer 1

GCF = 2y^2

Answer 2

2y^2(y^2 - 2y - 15)

now you need to factor the trinomial in the parentheses

Answer 3

I have no idea what to do next...

Answer 4

ok tghis will factor to the form
(x + a)(x + b)

where ab = the last term ( -15 ) and a + b = -2 ( the coefficient of 2)

ab = -15

one possibility = -5 and +3
what is the value of a + b ?

Answer 5

2y^2(y^2 - 2y - 15)

Answer 6

a + b = -5 + 3 = -2

so that it

factors are

2y^2(y - 5)(y + 3)

Answer 7

oooooh ok, thank you !

Answer 8

yw

to get the factors you do this

-5 and + 3 give us the 2 middle terms -5y + 3y

y^2 - 2y - 15 = y^2 -5y + 3y - 15
grouping in pairs:

= y(y - 5) + 3 (y - 5)

= (y + 3)(y - 5)

Answer 9

So, if you add it together, it equals the middle term, but when you multiply it, it equals the last term?

Answer 10

right

Answer 11

eg x^2 - 5x + 6

what do you think the 2 numbers would be in this case ?