How do you solve x^2+x-20=0?

1 Answer
Mar 28, 2016

x=4,-5

Explanation:

color(blue)(x^2+x-20=0

First, Factor the equation:

rarrx^2+5x-4x-20=0

rarrx(x+5)-4(x+5)=0

color(purple)(rarr(x-4)(x+5)=0

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Next, set both equations equal to zero, and solve.

rarrx-4=0

Add four to each side, and solve:

rarrxcancel(-4+4)=0+4

color(green)(rArrx=4

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rarrx+5=0

Subtract 5 from each side, and solve:

rarrxcancel(+5-5)=0-5

color(green)(rArrx=-5

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:.color(indigo)( ul bar |x=4, -5|