Question 698793: 5x2-20x=0. The problem is 5xto the second power
Answer by Simnepi(216)   (Show Source):
You can put this solution on YOUR website! Because the unknown (x) is raised to the power 2 there will be 2 possible values for x.
First we can factorise the expression by removing a common factor.
Both terms on the left hand side of the equals sign have an x in them (5x^2 is 5*x*x and 20x is 20*x) so we can remove it, the x, to the outside of a bracket thus
x(5x-20) = 0
Because this equals 0(zero) one of the terms in the above expression must equal zero since zero times anything is always zero
This means that
x (the term outside the bracket) = 0 (this is one possible value for x)
OR
5x-20 (the term inside the bracket) = 0
we now solve this bit to find out the other value for x
5x-20 = 0 which means that
5x = 20
so x = 4 (your other value for x)
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