How would you solve this?

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Answer 1 · 2017-12-04T11:25:52

See below.

$(-b +-sqrt(b^2-4ac))/(2a)$

Plugging in values:

$(-(-31)+-sqrt((-31)^2-(4(20)(12))))/(2(20))$

$(31+-sqrt((961)-(960)))/(40)$

$(31+-sqrt((1)))/(40)=>x=4/5 and x=3/4$

These are sine ratios, so we need:

$sin^-1(4/5)=0.92730$

For: $0<= x <2pi$

$0.92730, pi-0.9273=2.2143$

$sin^-1(3/4)=0.84806$

$0.84806, pi-0.84806=2.2935$

So solutions are:

$color(blue)(0.9273 , 2.2143 ,0.8481 , 2.2935$