How do you solve 5x^2 + 9x - 2 =0 using the quadratic formula?

2 Answers
Mar 20, 2016

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Explanation:

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Quadratic formulaQuadratic formula

Mar 20, 2016

x=1/5,-2

Explanation:

color(blue)(5x^2+9x-2=0

This is a Quadratic equation (in form ax^2+bx+c=0)

Use Quadratic equation

color(brown)(x=(-b+-sqrt(b^2-4ac))/(2a)

Where

color(red)(a=5,b=9,c=-2

Substitute the values

rarrx=(-9+-sqrt(9^2-4(5)(-2)))/(2(5))

rarrx=(-9+-sqrt(81-4(5)(-2)))/(10)

rarrx=(-9+-sqrt(81-(-40)))/(10)

rarrx=(-9+-sqrt(81+40))/(10)

rarrx=(-9+-sqrt(121))/10

rArrx=(-9+-11)/(10)

Now we have 2 solutions

color(orange)(rArrx=(-9+11)/(10)=2/10=1/5

color(indigo)(rArrx=(-9-11)/(10)=-20/10=-2

color(green)( ul bar|:.x=1/5,-2|