Question

What is the factored form of the expression? 120y^2 – 63y – 147

Answer 1

Answer:

3(5y   -     7)(8y +   7  )

Step-by-step explanation:

120y^2 – 63y – 147

Factor out a 3

3(40y^2 -21y -49)

40 = 1*40, 2*20  4*10  5*8

49 = 1*49 and 7*7

We need to play with the combinations to get -21 when added together

I will try

3(5y        7)(8y    7  )

We need the bigger one to be negative

5*7  + -8*7 = 35-56 = -21

So the 7 that multiplies by the 8 must be negative

3(5y   -     7)(8y +   7  )