The first term is, x2 its coefficient is 1 .
The middle term is, +4x its coefficient is 4 .
The last term, "the constant", is -7
Step-1 : Multiply the coefficient of the first term by the constant 1 • -7 = -7
Step-2 : Find two factors of -7 whose sum equals the coefficient of the middle term, which is 4 .
-7 + 1 = -6 -1 + 7 = 6