Learn how to solve problems step by step online. Solve the trigonometric equation 2cos(x)^2-5cos(x)+-3=0. We can try to factor the expression 2\cos\left(x\right)^2-5\cos\left(x\right)-3 by applying the following substitution. Substituting in the polynomial, the expression results in. Factor the trinomial 2u^2-5u-3 of the form ax^2+bx+c, first, make the product of 2 and -3. Now, find two numbers that multiplied give us -6 and add up to -5.

Solve the trigonometric equation 2cos(x)^2-5cos(x)+-3=0