SOLUTION: X squared minus 3x equals 28 by factoring

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Question 1061379: X squared minus 3x equals 28 by factoring
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
TRADITIONAL APPROACH:
x%5E2-3x=28
x%5E2-3x-28=0
The factored form will look like this:
%28x%2B%22___%22%29%28x%2B%22___%22%29=0
You look for a pair of factors of -28 ,
whose product is -28,
and whose sum is -3.
Since 4%2A7=28 and -7%2B4=-3 ,
you fill the blanks with -7 and 4 to get
highlight%28%28x-7%29%28x%2B4%29=0%29 .
So, system%28x-7=0%2C%22or%22%2Cx%2B4=0%29 ---> highlight%28system%28x=7%2C%22or%22%2Cx=-4%29%29

AN ALTERNATE IDEA:
x%5E2-3x=28
x%28x-3%29=28
I am looking for two numbers
whose product is 28 ,
and whose difference is 3 .
system%28x=7%2Cx-3=4%29 works,
and so does system%28x=-4%2Cx-3=-7%29 .
So, highlight%28system%28x=7%2C%22or%22%2Cx=-4%29%29