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#