The cost for 7 dance lessons is $82.The cost for 11 lessons is $122. Write a linear equation to find the ntotal cost C for L lessons.

Question

Then use the equation to find the cost of 4 lessons

Answer 1

1) Write out the 2 points.

 

(7,82)

(11,122)

 

2) Find the slope (change in y divided by change in x).

 

Slope = (122-82) / (11-7) = 40/4 = 10

 

3) Pick one of the points and insert it into point slope form.

 

y - 82 = 10(x-7)

y-82 = 10x-70

y = 10x + 12

 

4) Check your answer on the other point.

 

82 = 10(7) + 12

82=82