What is the answer to this problem i need i don't really understand?

What is [tex] {7}^{98 + \sqrt{4} } - 3 \times (64 \div 2 + 4 - 36) \times a = a + 36[/tex]?

The scale for a map is 20 miles = 1/2 inch. the distance between two towns on the map is 3 3/4 inches. what is the actual distance between these towns? 150 miles 38 miles 75 miles 135 miles

Find the value of the variable and the length of each secant segment.