Question

i need help

Answer 1

Find the product of (2x + 5y)(2x − 5y).

4x2 − 20xy + 25y2

4x2 + 20xy + 25y2

4x2 + 25y2

4x2 − 25y2

Answer 2

@nader1

Answer 3

do you have any idea?

Answer 4

Let me do the first one to show you....

F (first), O (outside), I (inside), L (last) -- the FOIL method.

lets look at your first problem...
(2x + 5y)(2x - 5y)
Start with F (first)...the first numbers in each set of parenthesis
(2x)(2x) - multiply = 4x^2
Now do O (outside)...the outside numbers..
(2x)(-5y) - multiply = -10xy
now do I (inside)...the inside numbers
(5y)(2x) - multiply = 10xy
now L (last)...the last numbers in the set of parenthesis
(5y)(-5y) - multiply = -25y^2

Now put them together...
4x^2 - 10xy + 10xy - 25y^2 (combine like terms)
4x^2 - 25y^2 (as you can see, the 10xy's cancel each other out)

so your answer is : 4x^2 - 25y^2

It is really not that hard once you learn how to do it.
Now just do the second problem that way....if you have any problems, track me down :)

Answer 5

not at all

Answer 6

The product of (a − b)(a − b) is a perfect square trinomial.

Sometimes

Always

Never

Answer 7

If you multiply each term in the first set of parentheses by each term in the second set of parentheses you get:

a^2 - 2ab + b^2

Answer 8

I am not exactly sure where to go from here....

Answer 9

@nader1 do you know?

Answer 10

The answer is "Always". Think about this perfect square trinomial: (a - b)² = a² - 2ab + b².