SOLUTION: I am having a problem factoring this one 14a^(2)-45a-14

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Question 452963: I am having a problem factoring this one 14a^(2)-45a-14
Found 3 solutions by mananth, ikleyn, MathTherapy:
Answer by mananth(16949) About Me  (Show Source):
You can put this solution on YOUR website!
Find the roots of the equation by quadratic formula

a= 14 ,b= -45 ,c= -14

b^2-4ac= 2025 + 784
b^2-4ac= 2809
sqrt%282809%29=53

x=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29
x1=%28-b%2Bsqrt%28b%5E2-4ac%29%29%2F%282a%29
x1=%2845%2Bsqrt%282809%29%29%2F%2828%29
x1=(45+ 53)/28
x1=3.5
x2=(45-53)/28
x2= -0.29

Answer by ikleyn(53614) About Me  (Show Source):
You can put this solution on YOUR website!
.
I am having a problem factoring this one 14a^2-45a-14.
~~~~~~~~~~~~~~~~~~~~~~~~


        The standard treatment of this problem and many other similar problems is to find
        the roots of a polynomial and then to decompose the polynomial.
        @mananth in his post started the job, but not completed it, so I came to do everything
        from the beginning to the end.


Find the roots of the given polynomial using the quadratic formula

    d = b^2 - 4ac = 45^2 - 4*14*(-14) = 2809

    x%5B1%5D = %28-b+%2B+sqrt%28d%29%29%2F%282a%29 = %28-%28-45%29+%2B+sqrt%282809%29%29%2F28 = %2845%2B53%29%2F18 = 98%2F28 = 7%2F2;

    x%5B2%5D = %28-b+-+sqrt%28d%29%29%2F%282a%29 = %28-%28-45%29+-+sqrt%282809%29%29%2F28 = %2845-53%29%2F18 = -8%2F28 = -2%2F7.


Therefore, the decomposition of our polynomial is

    14a^2 - 45a - 14 = 14%2A%28a-7%2F2%29%2A%28a%2B2%2F7%29 = (2a-7)*(7a+2).


ANSWER.  14a^2 - 45a - 14 = (2a-7)*(7a+2).

Solved.



Answer by MathTherapy(10719) About Me  (Show Source):
You can put this solution on YOUR website!
I am having a problem factoring this one 14a^(2)-45a-14

14a%5E2+-+45a+-+14
Use the "ac" method
14a%5E2+-+49a+%2B+4a+-+14 ---- Replacing - 45a with - 49a + 4a
7a%282a+-+7%29+%2B+2%282a+-+7%29
highlight%28%287a+%2B+2%29%282a+-+7%29%29