how do u foil( or solve) a math problem such as (x-5)(x + 5)?

Answer 1

2(x)-5x+5x-10....i believe...

Answer 2

You call it First, Outer, Inner, Last or FOIL. Take the X in the first parenthesis and multiply it by the X in the second parenthesis.Next take the X from the first parenthesis and multiply the +5 in the second parenthesis. Now take the -5 from the fist parenthesis and multiply it by the X in the second parenthesis. Lastly take the -5 in the first parenthesis and multiply it by the +5 in the last parenthesis. Now gather all your like terms from the result of the multiplications and this should give you an answer of x^2-25 which is a perfect square.

To make sure you are following: x*x= x^2, x*+5= +5x,
-5*x= -5x,and lastly -5*+5= -25. Combining like terms leaves: x^2-25. I hope this helps you.

Answer 3

X^2 -25= (x-5)(x+5)

Answer 4

To solve for (x-5)(x + 5) using FOIL

x * x = x^2
x * 5 = 5x
-5 * x = -5x
-5 * 5 = -25

x^2 + 5x - 5x - 25 = x^2 - 25, which is the same as (x-5)(x + 5)

Once you get the hang of it, you will be able to just look at these and know what they are without having to use FOIL.

Answer 5

first (x-5)(x+5) = 0
then x = either -5 or 5
this is to solve x
if you want expand the brackets then
you multiply the first x by the second bracket
then you multiply the -5 by the second bracket like this
=x'2+5x-5x-25
=x'2-25

Answer 6

FOIL--first, outside, inside, last
First - multiply the first term in each set of parenthesis
Outside - multiply the two terms on the outside
Inside - multiply both of the inside terms
Last - multiply the last term in each set of parenthesis

Answer: x square + 5x - 5x-25 the +5x and -5x cancel out leaving you with x squared - 25.

Answer 7

x2+5x-5x-25=0
the negative and pos. 5x cancel each other out so: x2-25=0
next carry the -25 to the right of the equals by changing the negative to the positive:
x2=25 so five times five equals 25, therefore
x=5

Answer 8

x^2-25

Answer 9

once you do (4x+5)^2 it incredibly is (4x+5)(4x+5) then you definately might desire to distribute 16x^2+20x+20x+25 the two 20s come from once you multiply each 4x with the aid of the 5 in the different set of parenthesis. In different words once you have equations like this you will possibly be able to desire to take each # and multiply it with the aid of the two #s in the different parenthesis.

Answer 10

an easy solution....
use the identity (a+b) (a-b) = a square- b square
a=x, b= 5
so,
(x-5)(x+5)= x square - 5 square
=x square - 25

Answer 11

it's difference of squares.
the answer is x^2 - 25