SOLUTION: {{{5x^2+22x=-8}}}

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Question 24105: 5x%5E2%2B22x=-8
Answer by rapaljer(4671) About Me  (Show Source):
You can put this solution on YOUR website!
5x%5E2%2B22x=-8

This is a quadratic equation, so set it equal to zero:
5x%5E2%2B22x%2B8=+0

If it factors it needs to begin with 5x*x!
(5x + _____)(x+_____)= 0

The last times last must be two numbers whose product is 8: 1*8 or 2*4

Try the 2*4, and place the 4 in the last space so the OUTER times OUTER will be 5x*4 = 20x, and the INNER times INNER must be 2*x = 2x, for a total of 22x.

(5x+2)(x+4) = 0

There are two solutions:
5x+2 = 0
5x= -2
x= -2/5

x+4 = 0
x=-4

If you need extra help on this factoring problem, then see my website by clicking on "rapaljer", then "Basic Algebra", then "Samples of Basic Algebra: One Step at a Time", "Chapter 2", "Advanced Factoring of Trinomials."

R^2 at SCC