Answer:
(a - 3) • (a - 4)
Explanation:
The first term is, a2 its coefficient is 1 .
The middle term is, -7a its coefficient is -7 .
The last term, "the constant", is +12
Multiply the coefficient of the first term by the constant 1 • 12 = 12
Find two factors of 12 whose sum equals the coefficient of the middle term, which is -7 .
-12 + -1 = -13
-6 + -2 = -8
-4 + -3 = -7 That's it
Rewrite the polynomial splitting the middle term using the two factors, -4 and -3
a2 - 4a - 3a - 12
Add up the first 2 terms, pulling out like factors :
a • (a-4)
Add up the last 2 terms, pulling out common factors :
3 • (a-4)
Add up the four terms
(a-3) • (a-4)
Really hope this helps :)