Question

factor:

1. 81p^2r^2-4

2.-3x^2+75

3. 36r^2+60rp+25p^2

Answer 1

u need to factorise all three?

Answer 2

\[\left\{81 p^2 r^2-4,75-3 x^2,25 p^2+60 p r+36 r^2\right\}\to \]\[\left\{(9 p r-2) (9 p r+2),-3 (x-5) (x+5),(5 p+6 r)^2\right\} \]

Answer 3

Yes all 3

Answer 4

is that clear?

Answer 5

i'm still a bit confused but I'm trying to figure out. I understand the 1st one. but wouldn't I have to change it since 9 is the a squared 3?

Answer 6

vch one u mean? the 1st one?

Answer 7

I need help one by one

Answer 8

1.81p^2r^2-4
This is the of the form a^2-b^2.
a^2-b^2=(a-b)(a+b)
Here a^2=81p^2r^2
so a=sqrt(81p^2r^2)
=9pr
b^2=4
so b=2
Is it clear?

Answer 9

no still confused. Our teacher is teaching us factoring but only wants us to concentrate on factoring squared #'s at the moment. ........ Ok wait I see what you did

Answer 10

ok so (9pr+2)(9pr-2) .... is that it or do we have to continue factoring because 9 is square of 3?

Answer 11

no that's all.

Answer 12

ok then let me try the others.

Answer 13

-3x^2+75 common factor is 3 so -3(x^2-25) yes

Answer 14

36r^2+60rp+25p^2 would be 6r(6r+10rp)+5(5)

Answer 15

is this correct?

Answer 16

-3(x^2-25) is correct bt u can factorise (x^2-25) further.

Answer 17

how? -3(x-5)(x+5)

Answer 18

(x^2-25)
(a^2-b^2)=(a-b)(a+b)
a^2=x^2
so a=x
b^2=25
so b=5
therefore (x^2-25=(x-5)(x+5)
Is it clear?

Answer 19

ok So I got it right? -3(x-5)(x+5)

Answer 20

are you still there?

Answer 21

yes.

Answer 22

what about this one.... 6r(6r+10rp)+5(5) is this correct?

Answer 23

u shud work that ques in this way.
36r^2+60rp+25p^2
=36r^2+30rp+30rp+25p^2
=6r(6r+5p)+5p(6r+5p)
=(6r+5p)(6r+5p)
=(6r+5p)^2
is it clear?

Answer 24

Ok let me take a look to make sure I understand

Answer 25

im confused about this one. Because there is one I had before that looked like this.... 4x^2-12xy+9y^2 = (2x-2xy+3y)(2x+6xy+3y) .... wouldn't I do the same here?

Answer 26

. 4x^2-12xy+9y^2 = (2x-3y)^2

Answer 27

See when u multiply (2x-2xy+3y)(2x+6xy+3y) if u get 4x^2-12xy+9y^2

Answer 28

so I did not do that one correct either?

Answer 29

yes.

Answer 30

i understood the first one you broke down. Now Im confused about 4x^2-12xy+9y^2

Answer 31

4x^2-12xy+9y^2
=4x^2-6xy-6xy+9y^2
=2x(2x-3y)-3y(2x-3y)
=(2x-3y)(2x-3y)
=(2x-3y)^2

Answer 32

This is harder for me to comprehend. It gets frustrating when others in class find it so simple. I understood. Let me try one on my own to check for understanding

Answer 33

ha k.

Answer 34

Im going to attempt
121x^2+22x+1
=121x^2+11x+11x+1
=11x(11x+1)1(11x+1)
=(11x+1)(11x+1)
=(11x+1)^2

Answer 35

is this correct?

Answer 36

yes. correct.:)

Answer 37

thank you so very much. Do you have the formula for this...... the way you explained with a & b?

Answer 38

u r welcome.:)
(a+b)^2=a^2+2ab+b^2