R-6+n, when r=3 and n=2

Two line segments are shown in the figure below. suppose that the length of the line along the x-axis is 6, and the length of the hypotenuse of the triangle is 10. what is the equation of the hypotenuse line (shown in red, below)?

At your job you're paid $50 per week plus $3 per sale at least how many saled do you need to make in order to have over $250

What is the domain of the step function f(x)=[2x]-1?