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)
