Express as a single integral

Question

How do I express these as a single integral ? 

 

∫f (lower :-2 upper:2) + ∫f (lower:2 upper:5 ) - ∫f (lower:-2 upper : -1)

Answer 1

∫_-2² f(x) dx + ∫₂⁵ f(x) dx - ∫_-2^-1 f(x) dx = [ ∫_-2² f(x) dx - ∫_-2^-1 f(x) dx] + ∫₂⁵ f(x) dx = ∫_-1² f(x) dx + ∫₂⁵ f(x) dx =

= ∫_-1⁵ f(x) dx