Stine said:16x^2 + 36x +9=
(8x+3) (12x+3)
I tried several different ways but I have not come up with the correct answer yet. Can someone help me? Thank you!
jwpaine said:Count Iblis said:Stine said:16x^2 + 36x +9=
(8x+3) (12x+3)
I tried several different ways but I have not come up with the correct answer yet. Can someone help me? Thank you!
On both sides of the equation there is a constant term of 9, so they cancel. This means that x = 0 is a solution. Divide this away and you are left with a linear equation.
0 is NOT a zero for this polynomial!
Cheers,
John
jwpaine said:I think you did the same as I did, initially:
his equation is \(\displaystyle \L 16x^{2} + 36x +9 -(8x+3) (12x+3) = 0\)
=
\(\displaystyle \L -80x^2 - 24x = 0\)
\(\displaystyle \L -80{x}^2-24{x}\) can be factored into -8 x (3 + 10 x) = 0
so -8x = 0 or (3x+10) = 0
x = 0 or x = -(10/3)
And those are the two x intercepts.
This is the answer, Stine: now that everyone has thrown you a different way of solving it.
16x^2 + 36x +9=
(8x+3) (12x+3)
jwpaine said:
This cannot be intuitively factored using whole numbers.
Learn how to solve a polynomial using the completing the square method. This is how the quadratic formula is derived. Learn how to complete the square, and WHY the quadratic formula works. It is IMPORTANT to understand besides just plugging and chugging with the formula.
These links should help.
http://www.purplemath.com/modules/sqrquad2.htm#formula
http://www.purplemath.com/modules/sqrquad.htm
Cheers,
John