Math Is Fun Forum

mathxyz

Member

From: Brooklyn, NY

Registered: 2024-02-24

Posts: 1,053

Factor Completely

Factor Completely.

Problem 108; page 58.

9y^2 + 9y - 4

I think factor by grouping works here.

9(-4) = -36

12(-3) = -36 and 12 + (-3) = 9.

9y^2 + 12y - 3y - 4

9y^2 + 12y = group A

-3y - 4 = group B

Factor group A

GCF = 3y

3y(3y + 4)

Factor group B

GCF = -1

-1(3y + 4)

I now have 3y(3y + 4) - 1(3y + 4)

My answer: (3y - 1)(3y + 4).

You say?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,627

Re: Factor Completely

Correct.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

mathxyz

Member

From: Brooklyn, NY

Registered: 2024-02-24

Posts: 1,053

Re: Factor Completely

Correct.

Bob

Very good. I have decided to include precalculus to my self-study journey. College Algebra and Precalculus have more or less the same topics except for trigonometry, polar equations, math induction and a few others. If I go through two textbooks ONE AT A TIME, I will never reach Calculus 1.

I can start Calculus with you tomorrow and do well but I also think that studying College Algebra and Precalculus SIMULTANEOUSLY will increase my math skills and provide the confidence I need to UNDERSTAND Calculus not just memorize a bunch of formulas.

You say?

P. S. I will give you the name of my precalculus textbook for you to freely download when I get home. By the way, I passed precalculus with an A minus at Lehman College in the Spring 1993 semester. So, precalculus is also a revisit to material learned long ago when I was young.