Functions and equations

Question

the equation below represents total amt charged,y, by 2 different plumbers. Below are a function of the number of hours worked, X. Plumber A: y=20x+60

Plumber B: y=40x

graphs of these functions cross at point (3,120) what does this signify?

a) point (3,120) is the slope of system of equations

b) point (3,120) is when plumbers worked 120 hours

c) point (3,120) is y-intercept of system of eq 

d) point (3,120) is solution

Answer 1

Kim, let's look at each choice.

 

a) A point does not give you slope.

 

b) The hours worked is the independent variable, which would be listed first.

 

 

 

c) The x-value of the y intercept is ALWAYS 0.

 

d) Any point along the first line is a solution for that equation. The same goes for the second. The point where they meet is the solution for BOTH equations.

 

Your answer is d.