-2cosx*(-sinx)+√3sinx=0
sinx(2cosx+√3)=0
sinx=0⇒x=πn
cosx=-√3/2⇒x=+-5π/6+2πn
(5x - 1)(x + 2) + 3(x - 4)(x + 4) = 2(2x + 3)² - 8
5x² + 10x - x - 2 + 3(x² - 16) = 2(4x² + 12x + 9) - 8
5x² + 9x - 2 + 3x² - 48 = 8x² + 24x + 18 - 8
8x² + 9x - 50 - 8x² - 24x - 10 = 0
- 15x = 60
x = - 4