Mathematics

Question

which of the following are solutions to 2x^2 -8x -90
A) 2
B) -5
C) -7
D) 9
E) 15
F) 5
G) 7

1 Answer

  • Please equate 2x^2 -8x -90 to zero:    2x^2 -8x -90=0

    Next, reduce 
    2x^2 -8x -90=0 by div. all terms by 2:    x^2 -4x -45=0

    Next, factor the poly:  (x-9)(x+5) = 0

    Set each factor = to 0 and solve for x:

    x-9=0 => x=9
    x+5=0 => x= -5
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