(4-10i)+(7-3i)
a. -3-13i
b. -3-7i
c. 11-7i
d. 11-13i

Donald has x twenty-dollar bills and 11 ten-dollar bill. how much money does donald have? write your answer as an expression.

Askateboard ramp is in the shape of a right triangle what is the height of the ramp

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?