Answer:
The ordered pair (6,25) is a solution to both
and 
Step-by-step explanation:
Part 7)
<em>step 1</em>
Find the equation of the line with positive slope
take the points (0,15) and (9,30)
<em>Find the slope</em>
The formula to calculate the slope between two points is equal to

substitute the given values


simplify

Find the equation of the line in slope intercept form

we have


substitute

<em>step 2</em>
Find the equation of the line with negative slope
take the points (0,40) and (8,20)
<em>Find the slope</em>
The formula to calculate the slope between two points is equal to

substitute the given values


simplify

Find the equation of the line in slope intercept form

we have


substitute

step 3
Find the solution of the system
we know that
The solution of the system of equations is the intersection point both graphs
The intersection point is (6,25) ----> see the graph
therefore
The ordered pair (6,25) is a solution to both
and
