Michelle has the problem $(2x + 3)^2 − 3(2x + 3) − 10 = 0$ and is thinking of expanding the $(2x + 3)$ terms and then solving. Erin suggests that she let $a = 2x + 3$ then solve $a^2 − 3a − 10 = 0$. Use Erin’s suggestion to solve for $a$ and then use your solutions to find the values of $x$.