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

1 Answer
Alan P.
Mar 17, 2016

Re-write the n equation in standard form then apply the quadratic formula

Explanation:

General standard form for a quadratic:
color(white)("XXX")color(red)(a)x^2+color(blue)(b)x+color(green)(c)=0
Quadratic formula for roots:
color(white)("XXX")x=(-color(blue)(b)+-sqrt(color(blue)(b)^2-4color(red)(a)color(green)(c)))/(2color(red)(a))

2x^2+9x=8
expressed in standard form:
color(white)("XXX")color(red)(2)x^2+color(blue)(9)+color(green)((-8))=0

Solutions:
color(white)("XXX")x=(-color(blue)(9)+-sqrt(color(blue)(9)^2-4(color(red)(2))(color(green)(-8))))/(2(color(red)(2)))

color(white)("XXXx")=(-9+-sqrt(145))/4

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