How do I expand and simplify a double bracket equation?

For example: 3(2a + 5) + 5(a - 2)
The key is to approach this question in two steps, with the first step being to expand the brackets before then simplifying where possible. A good method for expanding the brackets is using 'the claw method'.In this example you would multiply whats outside the brackets with whats inside, leaving (6a + 15) + (5a -10). Then to simplify you match similar terms to leave 11a + 5.