How do you factor completely 12z2+7z12?

2 Answers
May 19, 2018

See below

Explanation:

Two alternatives: use quadratic formula or complete square (a little bit complicate in this case). The use of Riffini's method is also available but in this case is not quite evident

Quadratic formula:

12z2+7z12=0

z=7±49+57624=7±2524 from here two solutions

z=34 and z=43

Then factoring is (z34)(z+43)=12z2+7z12

May 19, 2018

(3z+4)(4z3)

Explanation:

12z2+7z12

=12z2+16z9z12

=4z(3z+4)3(3z+4)

=(3z+4)(4z3)