let tanx = y or just use it as a variable
tan^2x -3tanx - 2
a = 1 , b = -3 , c = -3
quadratic formula
tanx = [-b + sqrt(b^2 - 4 ac) ]/ 2 a
= [ 3 + sqrt( 9 +12)] / 2 = 3.56
tanx = [-b - sqrt(b^2 - 4 ac) ]/ 2 a
= [ 3 - sqrt( 9 +12)] / 2 = -0.56
x = 1st or 3rd quadrant
x = tan^-1(3.56) = 74.3 (1st)
x = 180 + 74.3 (3rd)
x = tan^-1(-0.56) two options either 2nd quarter or 4th quadrant
x = 180 - 29.2 ( 2nd)
x = 360 - 29.2 ( 4th)