Answer:
(z+7)*(z+4)
Explanation:
The first term is, z2 its coefficient is 1 .
The middle term is, +11z its coefficient is 11 .
The last term, "the constant", is +28
Step-1 : Multiply the coefficient of the first term by the constant 1 • 28 = 28
Step-2 : Find two factors of 28 whose sum equals the coefficient of the middle term, which is 11 .
-28 + -1 = -29
-14 + -2 = -16
-7 + -4 = -11
-4 + -7 = -11
-2 + -14 = -16
-1 + -28 = -29
1 + 28 = 29
2 + 14 = 16
4 + 7 = 11 That's it
Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above, 4 and 7
z2 + 4z + 7z + 28
Step-4 : Add up the first 2 terms, pulling out like factors :
z • (z+4)
Add up the last 2 terms, pulling out common factors :
7 • (z+4)
Step-5 : Add up the four terms of step 4 :
(z+7) • (z+4)
Which is the desired factorization