How do you solve #-4x^2+x+9=0# using the quadratic formula?

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Answer 1 · 2016-07-07T16:35:56

#x=1/8 + sqrt145/8# or #x=1/8 - sqrt145/8#

The Quadratic Formula is #(-b+-sqrt(b^2-4ac))/(2a)#

A Quadratic Equation is #ax^2 + bx + c = 0#

For the equation #-4x^2+x+9=0#

#a=-4#
#b=1#
#c=9#

Plug in the values

#(-1+-sqrt(1^2-4(-4)9))/(2(-4))#

#(-1+-sqrt(1+144))/(-8)#

#(-1+-sqrt(145))/(-8)#

#(-1)/-8 +-sqrt145/-8#

#1/8 + sqrt145/8# or #1/8 - sqrt145/8#