SOLUTION: Please help me solve this question: 7x^2-7x-1=0 I need the solutions for this problem. If you can help me figure out the F.O.I.L. method part of this problem I can do the rest.

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: Please help me solve this question: 7x^2-7x-1=0 I need the solutions for this problem. If you can help me figure out the F.O.I.L. method part of this problem I can do the rest.       Log On


   

Question 855115: Please help me solve this question: 7x^2-7x-1=0
I need the solutions for this problem. If you can help me figure out the F.O.I.L. method part of this problem I can do the rest. Thank you!
This is the part i am having trouble with:
(7x+1)(x-7) ???
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
(7x+1)(x-7) will not give the trinomial quadratic expression in your equation.

If you want to factor the left side of 7x%5E2-7x-1=0, then you can try to look for two number whose sum is -7 and whose product is -1. Try to arrange a form, (7x__a)(x___b). Can some combination be found? Integers?

There is the complication that coefficient on the x^2 term must be 7; no matter - we look for combinations of numbers at least which give -1 product.

(7x___)(x___) and we can only use 1 and -1. We have two ways to do this.
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%287x-1%29%28x%2B1%29=7x%5E2-1x%2B7x-1 ------ does not give us the quadratic we want.
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%287x%2B1%29%28x-1%29=7x%5E2%2Bx-7x-1-------still does not give us the quadratic we want.

USE THE GENERAL SOLUTION TO A QUADRATIC FORMULA.
Instead of carrying those solution steps for your example, I refer to a lesson about solving quadratic equations using completing the square or the general solution.
Solve a Quadratic Equation using the General Solution