Learn how to solve problems step by step online. Solve the trigonometric equation 9sin(x)^2+5sin(x)+-4=0. We can try to factor the expression 9\sin\left(x\right)^2+5\sin\left(x\right)-4 by applying the following substitution. Substituting in the polynomial, the expression results in. Factor the trinomial 9u^2+5u-4 of the form ax^2+bx+c, first, make the product of 9 and -4. Now, find two numbers that multiplied give us -36 and add up to 5.

Solve the trigonometric equation 9sin(x)^2+5sin(x)+-4=0