Prove that sin(x)^2 - 5cos(x)^2 = 6sin(x)^2 - 5

5 = 5(cos(x)^2 + sin(x)^2) = 5cos(x)^2 + 5sin(x)^2=> 5 - 5cos(x)^2 = 5sin(x)^2=> sin(x)^2 + 5 - 5cos(x)^2 = 6sin(x)^2=> sin(x)^2 - 5cos(x)^2 = 6sin(x)^2 - 5