Riley can swim 1/2 mile in 3/4 hour. what is the unit rateof miles per hours

Can someone me out here number 4 plz

Prove that the value of the expression 7^8–7^7+7^6 is divisible by 43.

Aclothing store has the sign shown in the shop window. pani sees the sign and wants to buy 3 shirts and 2 pairs of jeans. the cost of each shirt before the discount is $12, and the cost of each pair of jeans is $19 before the discount. write and simplify an expression to find the amount pani pays if a $3 discount is applied to her total