I don’t know how to do this, can someone please explain, it would mean a lot!!!

Answer:
a) 17
Step-by-step explanation:
The integral is the area under the curve.
The area between x=1 and x=7 equals the area between x=1 and x=5 plus the area between x=5 and x=7.
∫₁⁷ f(x) dx = ∫₁⁵ f(x) dx + ∫₅⁷ f(x) dx
∫₁⁷ f(x) dx = 7 + 10
∫₁⁷ f(x) dx = 17