Question

7. Which of the following can be determined from the graph below?

Answer 1

Answer:

The ordered pair (6,25) is a solution to both

$y=-\frac{5}{2}x+40$  and  $y=\frac{5}{3}x+15$

Step-by-step explanation:

Part 7)

step 1

Find the equation of the line with positive slope

take the points (0,15) and (9,30)

Find the slope

The formula to calculate the slope between two points is equal to

$m=\frac{y2-y1}{x2-x1}$

substitute the given values

$m=\frac{30-15}{9-0}$

$m=\frac{15}{9}$

simplify

$m=\frac{5}{3}$

Find the equation of the line in slope intercept form

$y=mx+b$

we have

$m=\frac{5}{3}$

$b=15$

substitute

$y=\frac{5}{3}x+15$

step 2

Find the equation of the line with negative slope

take the points (0,40) and (8,20)

Find the slope

The formula to calculate the slope between two points is equal to

$m=\frac{y2-y1}{x2-x1}$

substitute the given values

$m=\frac{20-40}{8-0}$

$m=-\frac{20}{8}$

simplify

$m=-\frac{5}{2}$

Find the equation of the line in slope intercept form

$y=mx+b$

we have

$m=-\frac{5}{2}$

$b=40$

substitute

$y=-\frac{5}{2}x+40$

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 $y=-\frac{5}{2}x+40$  and  

$y=\frac{5}{3}x+15$