# Math

posted by .

Factor

1. 8a^2-2ab-21b^2

2. 6m^2-90m+324

3.5x(2-x)+4x(2x-5)-(3x-4)

4. 9(y-1)^2-25

5. 3x^2-27(2-x)^2

• Math -

4. 9(y-1)^2 - 25 = [3(y-1)]^2 - 5^2
= [3(y-1)+5]*[3(y-1)-5]
= (3y-2)(3y-8)

5. 3x^2 - 27(2-x)^2
= 3[x^2 - 9(2-x)^2]
= 3[x^2 - [3(2-x)]^2]
= 3[(x+3(2-x)][x-3(2-x)]
= 3(x + 6 - 3x)(x - 6 + 3x)
= 3(-2x+6)(4x-6)
= 12(3-x)(2x-3)

It's late -- someone else do 1-3

## Similar Questions

1. ### Algebra

Factor 2ab(c-d)+10d(c-d) I would like to know how to do this. Thanks. (c-d) is a common factor, so you pull it out: (c-d)(2ab + 10d) Oh, then you can pull a 2 out: (c-d)(2)(ab + 5d) Thanks! you're welcome!! What do the letters stand …
2. ### math

what would it be if you took 324.76 and tryed to make it notation and in decimals and fractions 3.2476 x 10^2 and 324 76/100 324.76 is already in decimal form. As a fraction (mixed number), it is 324 76/100, which can be reduced to …
3. ### Math

1.3x^2+17x+10 2.5y^8-125 3.a^2-2ab-15b^2 *Please help me.You have to factor by completing. Let's look at #1: 3x^2 + 17x + 10 We have 2 and 5 as factors of the last term. What combinations can we do to arrive at the middle term?
4. ### Gr. 10 Math!

Factor by Grouping. PLEASE SHOW ME THE STEPS! 1.) 8a^2+12ab-3b^2-2ab 2.) x^2+5x+7x+35 3.)
5. ### Gr.10 Math!!!! urgent

Factor by Grouping. PLEASE SHOW ME THE STEPS! 1.) 8a^2+12ab-3b^2-2ab 2.) x^2+5x+7x+35
6. ### math

Hi, I need help with these questions: factor 6m^2-90m+324 8a62-2ab-21b^2 pls help
7. ### Algebra

Factor completely. Remember to look first for a common factor. Check by multiplying. If a polynomial is prime state this. a^2-2ab-3b^2
8. ### Algebra

Factor completely. Remember to look first for a common factor. Check by multiplying. If a polynomial is prime state this. a^2-2ab-3b^2
9. ### Polynomials

State whether the following equations are sometimes, always or never true. a) a^2-2ab-b^2= (a-b)^2, bis not equal to 0 b) a^2+ b^2= (a+b)(a+b) c) a^2-b^2= a^2-2ab+b^2 d) (a=b)^2 = a^2+2ab+b^2 I don't understand what these questions …
10. ### Math

Factor the following expression completely: 2ab+6a+12abc

More Similar Questions