Anybody know the answer to number 3

Evaluate the expression for the given value of the variable 7a - 4a for a =8

Reduce fractions expressing probability to lowest terms. in 3,000 repetitions of an experiment, a random event occurred in 500 cases. the expected probability of this event is?

5. write an equation for the line that is parallel to the given line and that passes through the given point. y = –5x + 3; (–6, 3)