The cost for 7 dance lessons is $82. the cost for 11 is $122. write a linear equations to find the total cost C for L dance lessons. How much for 4 lessons?

(7,82) (11,122)

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

y = mx + b

slope (m) = 10

(7,82) ... x = 7 and y = 82

now we sub

82 = 10 (7) + b

82 = 70 + b

82 - 70 = b

12 = b

equation is : y = 10x + 12

or, in this problem, it is : C = 10L + 12 < = = ur equation

if there were 4 dance lessons.

C = 10 (4) + 12

C = 40 + 12

C = 52 < = = it would cost $52 for 4 dance lessons.