not sure what standard form is, but I can solve for x
so I'm assuming that x2 means x squared or x^2 so
x^2+7x+12=0
since it equals zero, if we can factor it, then
if we have xy=0 then x and/or y=0 so
to factor x^2+7x+12
find what 2 numbers multiply to get 12 and add to get 7 so
12=2 times 2 times 3 or 2 times 6 or 1 times 12 or 3 times 4
the numbesr are 4 times 3 so
x^2+7x+12
facotrs out to
(x+4)(x+3) so
x^2+7x+12=0
(x+4)(x+3)=0
set each to zero
x+4=0 and x+3=0
x+4=0
subtract 4 form both sides
x=-4
x+3=0
subtract 3 from both sides
x=-3
x=-4 or -3