SOLUTION: find solutions to equation x-5/x=4

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Question 73606: find solutions to equation x-5/x=4
Answer by ptaylor(2198) About Me  (Show Source):
You can put this solution on YOUR website!
find solutions to equation x-5/x=4
x-5%2Fx=4 First, multiply each term by x:
x%5E2-5=4x Next, subtract 4x from both sides:
x%5E2-4x-5=0 quadratic equation in standard form where:
A=1
B=-4
C=-5
By inspection, we can see that this quadratic can be factored:
%28x-5%29%28x%2B1%29=0
x=5
and
x=-1
A characteristic of quadratics that's useful to know is this:
If the quadratic can be factored, and the "A" coefficient is 1, then the "B" coefficient will be the sum of the factors of the "C" coefficient. In this case, the factors of the "C" coefficient that work are -5 and 1. For example:
%28x%2Ba%29%28x%2Bb%29=0 Use FOIL (First, Outer, Inner, Last) to expand:
x%5E2%2Bxa%2Bxb%2Bab=0 simplify
x%5E2%2B%28a%2Bb%29x%2Bab=0 and we can see that the "B" coefficient is a%2Bband the "C" factors are ab

Hope this helps---ptaylor