Help please!!

Find the equation of the line. Use exact numbers. y= x+

(note i put the graph in so plz )the graph shows the amount of water that remains in a barrel after it begins to leak. the variable x represents the number of days that have passed since the barrel was filled, and y represents the number of gallons of water that remain in the barrel. what is the slope of the line

What is the area of the trapezoid shown ?

How many solutions does the nonlinear system of equations graphed bellow have?