SOLUTION: Which equation is -3 not a solution? a)x^2-2x-15 b)x^2-21=4x c)2x^2+12x=-18 d)9+x^2=0 I appreciate your help!

Algebra ->  College  -> Linear Algebra -> SOLUTION: Which equation is -3 not a solution? a)x^2-2x-15 b)x^2-21=4x c)2x^2+12x=-18 d)9+x^2=0 I appreciate your help!      Log On


   

Question 713262: Which equation is -3 not a solution?
a)x^2-2x-15
b)x^2-21=4x
c)2x^2+12x=-18
d)9+x^2=0
I appreciate your help!
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Which equation is -3 not a solution?
Note: (-3)^2 = 9
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a)x^2-2x=15
9 -2*-3 = 15
9+6 = 15
true
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b)x^2-21=4x
9 - 21 = -12
true
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c)2x^2+12x=-18
2*9 -36 = -18
true
---------------------
d)9+x^2=0
9 + 9 = 0
false
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Cheers,
Stan H.
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