Posted by Anonymous on .
Can someone show me how to solve these stepbystep? Please? Thank you.
Factor each polynomial by grouping. Check your answer.
1. 2r^2  6r + 12  4r
2. 14q^2  21q + 6  4q
3. w^3 4w^2 + w  4
4. 2p^3  6p^2 + 15  5p

Algebra 1StepbyStep 
Reiny,
1.
2r(r  3) + 4(3  r) , ahhh, did you notice that the brackets are opposite? , so ..
= 2r(r3)  4(r  3)
= (r3)(2r4)
Use the same "trick" on the others if you have to. 
Algebra 1StepbyStep 
Anonymous,
My textbook says the answer is 2(r2)(r3), though.

Algebra 1StepbyStep 
Reiny,
Surely you could see that 2 was an additional common factor contained in my (2r4) factor.

Algebra 1StepbyStep 
Anonymous,
What? I don't understand what you mean.

Algebra 1StepbyStep 
Reiny,
look at my answer ...
(r3)(2r4)
= (r3)(2)(r2)
= 2(r3)(r2) 
Algebra 1StepbyStep 
Anonymous,
Oh.
My answers to the other equations:
2. ?
3. (w^2 + 1)(w  4)
4. (2p^2  5)(p  3) 
Algebra 1StepbyStep 
Anonymous,
2. (7q  2)(2q  3).

Algebra 1StepbyStep 
Reiny,
3 and 4 are correct
#2
14q^2  21q + 6  4q
= 7q(2q  3) + 2(32q)
= 7q(2q3)  2(2q3)
= (2q3)(7q2) 
Algebra 1StepbyStep 
Anonymous,
Thank you.