Answer
There are $435$ Representatives and $100$ Senators.
Work Step by Step
Let $x$ be the number of Representatives
Let $y$ be the number of Senators
Solving the problem $$(1)x = 5y - 65$$ $$(2)x + y = 535$$
Substituting (1) in (2) $$5y-65+y = 535$$ $$6y = 535+65 = 600$$ $$y = \frac{600}{6} = 100$$
Solving or $x$ $$x = 5*100 - 65 = 500 - 65 = 435$$