### Home > APCALC > Chapter 4 > Lesson 4.5.1 > Problem4-176

4-176.

Solve for $x$ in each equation. Assume $x$ is measured in radians. Hint: First use a substitution to make the problem easier.

1. $2\sin^2\left(x+1\right)-\sin\left(x+1\right)-1=0$

Let $U=\sin\left(x+1\right)$
so $2U^2−U−1=0$

Solve for $U$, then substitute to solve for $x$.

Remember to mention ALL solutions.

2. $( x ^ { 2 } - 2 x + 1 ) - 3 \sqrt { x ^ { 2 } - 2 x + 1 } = - 2$

Let $U = x^{2} − 2x + 1$