How high up on a wall will a 20-foot ladder touch if the foot of the ladder is placed 4 feet from the base of the wall?

Really need on these. i have no idea what to do

Find the x-intercept and y-intercept of the line. 3x + 5y = −15

The map shows the location of the airport and a warehouse in a city. though not displayed on the map, there is also a factory 112 miles due north of the warehouse.a truck traveled from the warehouse to the airport and then to the factory. what is the total number of miles the truck traveled?