Answer:
a: (x + 3)(x + 4)
Explanation:
assuming x^2 + 7x + 12 is the equation you are factoring
you would first multiply a * c
a is 1
b is 7
c is 12
1 * 12 = 12
then you take b and find what adds up to b but multiplies to ac
what adds up to 7 but multiplies to 12
3 and 4
so
you split the equation up like this
x^2 + 3x + 4x + 12
then you factor
x(x + 3) + 4(x + 3)
because x + 3 and x + 3 are the same we can do this
(x + 4)(x + 3)
that is your equation
so a is your answer
it doesnt matter if you have the (x + 3) or (x + 4) in the front