Factor the polynomial.

7x^2 + 68xy - 20y^2

We notice that it must be a product of 2 different thingummies

so we have

(x + / - y) (x + - / y)

we need to determine the spaces ad signs

we know that the signs are different since the end result is negative

so fidn the first one

7

factor

7=1 times 7

so we have

(1x + / - y) (7x + / - y)

factor end

-20=-1 and 20 or - 2 and 10 or - 4 and 5

we want the middle term to be positive so the bigger term must be positive

try the ones closest first

(x-4y) (7x+5y)

multiply out the middles and outers

5xy-28xy is not 68xy

try - 2 and 10

(x+10y) (7x-2y)

multily middles and outers

-2xy and 70xy=68xy

correct

answer is (x+10y) (7x-2y)

Factoring this down, would leave you with two happy expressions in parantheses. (x+10y) (7x-2y).

(AKA Factor out an x and a y to be able to simplify even more.)