### Instruction: Find the least value of $b$ such that $b^2+2b-15 \le 0$.### Response: I need to find the smallest value of $b$ that makes the quadratic expression negative or zero.
To do that, I can first factor the expression as $(b+5)(b-3)$.
Then, I can see that the expression is zero when $b=-5$ or $b=3$, and it is negative when $b$ is between those values.