Let y=2t+5, what does the number 5 represent?

What is the length of the unknown leg in the right triangle ?

The figure below shows rectangle abcd and the triangle eca on a coordinate plane.which of the following expressions represents the perimeter of triangle of triangle eca in units

Apackage of five erasers cost 0. $.39 at this rate how many how much would 60 erasers cost in dollars and cents