SOLUTION: Please help me solve this using the quadratic formula: 2x^2+x=21

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Question 136276: Please help me solve this using the quadratic formula:
2x^2+x=21

Found 2 solutions by stanbon, checkley77:
Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
solve this using the quadratic formula:
2x^2+x=21
2x^2+x-21 = 0
x = [-1 +- sqrt(1-4*2*-2)]/4
x = [-1 +- sqrt(17)]/4
============================
Cheers,
Stan H.

Answer by checkley77(12844)   (Show Source): You can put this solution on YOUR website!
2x^2+x=21
2x^2+x-21=0

x=(-1+-sqrt(1^2-4*2*-21])/2*2
x=(-1+-sqrt[1+168])/4
x=(-1+-sqrt169)/4
x=(-1+-13)/4
x=(-1+13/4
x=12/4
x=3 answer.
x=(-1-13)/4
x=(-14)/4
x=-3.5 answer.

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