Chapter 8.5, Problem 4QR

I need help on my homework Please evaluate the definite integral

Need help in business calculus.  I'm not sure how to solve for a and b when given integrals. For example, upper bound: 23, lower bound: 5 ∫f(x)dx - upper bound: 14, lower bound: 5 ∫f(x)dx=upper bound: b, lower bound: a ∫f(x)dx  How would do I solve for a and b?

accidently posted two questions. with this one