How do you solve #-8+9x^2+5=-9x^2+5#?

1 Answer
Oct 24, 2016

Answer:

#x=-2/3, 2/3#

Explanation:

Solve: #-8+9x^2+5=-9x^2+5#

Simplify.

#9x^2-3=-9x^2+5#

Add #3# to both sides.

#9x^2=-9x^2+5+3#

Add #9x^2# to both sides.

#9x^2+9x^2=5+3#

Simplify.

#18x^2=8#

Subtract #8# from both sides.

#18x^2-8=0#

This is a quadratic equation of the form #ax^2+bx+c#, where #a=18#, #b=0#, #c=-8#.

The value for #x# can be determined using the quadratic formula.

Quadratic Formula

#x=(-b+-sqrt(b^2-4*a*c))/(2a)#

#x=(-0+-sqrt(0^2-4*18*-8))/(2*18)#

Simplify.

#x=(+-sqrt(576))/36#

Simplify.

#x=+-(24)/36#

Simplify.

#x=+-4/9#

Simplify.

#x=+-2/3#

#x=-2/3, 2/3#