Question

What is the factored form of the expression?
4x^2-8ly^2

Answer 1

Hint:

\(\LARGE 4x^2 = (2x)^2\)

and

\(\LARGE 81y^2 = (9y)^2\)

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So

\(\LARGE 4x^2-81y^2\)

is the same as

\(\LARGE (2x)^2 - (9y)^2\)

Answer 2

Tell me what you get or if you need more help.

Answer 3

I really dont understand it at all

Answer 4

Do you remember the difference of squares rule?

Answer 5

ohh i get it now sorry :)

Answer 6

that's ok, so what's the final answer?

Answer 7

(2x-9y)^2

Answer 8

close, but not quite

Answer 9

the difference of squares rule is

\(\LARGE a^2 - b^2 = (a-b)(a+b)\)

Answer 10

what about (2x+9y)^2

Answer 11

not that either

Answer 12

compare

\(\LARGE (2x)^2 - (9y)^2\)

with

\(\LARGE a^2 - b^2 = (a-b)(a+b)\)

Answer 13

notice how a = 2x and b = 9y

Answer 14

yes

Answer 15

so

\(\LARGE a^2 - b^2 = (a-b)(a+b)\)

\(\LARGE (2x)^2 - (9y)^2 = (2x-9y)(2x+9y)\)

Answer 16

since \(\LARGE 4x^2-81y^2 = (2x)^2 - (9y)^2\)


This means


\(\LARGE 4x^2-81y^2 = (2x-9y)(2x+9y)\)

Answer 17

so its (2x-9y)(2x+9y)

Answer 18

yes

Answer 19

Thank you!
:)

Answer 20

sure thing