a-maths!!!!!

tan(2x+15°) - tan(x-75°) - tan(2x+15°)tan(x-75°) = 1
tan(2x+15°) - tan(x-75°) = 1 + tan(2x+15°)tan(x-75°)
[tan(2x+15°) - tan(x-75°)] / [1 + tan(2x+15°)tan(x-75°)] = 1
tan[(2x+15°) - (x-75°)] = 1
tan(x+90°) = 1
x+90° = 225° , 405°
x = 135° , 315°

2007-10-02 19:08:51 補充：
上面位人兄做少左個答案支持我啊...唔該