We start with the given:
tan(x)sin(20)+sin(20)=2tan(x)tan(x)sin(20)+sin(20)=2tan(x)
Then bring everything with x onto one side, place whatever else on the other side:
sin(20)=2tan(x)-tan(x)sin(20)sin(20)=2tan(x)−tan(x)sin(20)
Factorise tan(x)tan(x):
sin(20)=tan(x)(2-sin(20))sin(20)=tan(x)(2−sin(20))
Divide both sides by (2-sin(20))(2−sin(20)) so we leave tan(x)tan(x) alone
tan(x)=sin(20)/(2-sin(20)tan(x)=sin(20)2−sin(20)
Use the tan^-1tan−1 function to make tan(x)tan(x) into just xx
x=tan^-1(sin(20)/(2-sin(20)))x=tan−1(sin(20)2−sin(20))
Plug it into calculator:
x~~11.6558890174x≈11.6558890174 degrees