Tuesday

October 21, 2014

October 21, 2014

Posted by **Christian** on Monday, May 21, 2007 at 10:41pm.

1. 4x^2+12x+?

2. ?+90x+81

Could someone show me how to solve these?

Take the first:

factor out the 4

4x^2+12x+?

4( x^2 + 3x + ?)

take half the center term, and square it. half is 3/2, squared is 9/4

4( x^2 + 3x + 9/4)

Put the 4 back in...

4x^2 + 12x+9

(2x+3)(2x+3)

Second:

?+90x+81

Notice the last term is a perfect square, its square root is 9. Twice nine is eighteen.

Now to find the missing term, divide 90 by 18: five.

25x^2 + 90x + 81

(5x+9)(5x+9)

**Answer this Question**

**Related Questions**

Algebra 1 - 1. What is the excluded value for the rational expression x^2 - 4/3x...

Math - this question does not make sense to me. Add the proper constant to the ...

math,help - Is this trinomial a perfect square x^2-6x+9 if the trinomial starts ...

Math check - Complete the square: x^2 -12x. Which of the following is the ...

Algebra Help - What is the value of c so that y = x² + 9x + c is a perfect ...

Algebra - What is the value of c so that y = x² + 9x + c is a perfect square ...

Algebra 1--Please, help me! - 1. Maria has 8 cups of a fruit punch that consists...

Algebra 1--Please, help me! - 1. Maria has 8 cups of a fruit punch that consists...

alg3 - how do i factor the perfect square trinomial 9x2-12x+4

algebra - FIND THE VALUE OF K, SO THAT THE EXPRESSION IS A PERFECT SQUARE ...