The cost for 7 dance lessons is $82, the cost for 11 lessons is $122. write a linear equation to find the total cost (c) for (l) lessons. then use the equation to find the cost of 4 lessons.

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

y = mx + b
slope(m) = 10
(7,82)...x = 7 and y = 82
now we sub and solve for b, the y int
82 = 10(7) + b
82 = 70 + b
82 - 70 = b
12 = b

so ur equation is : y = 10x + 12

when x = 4
y = 10(4) + 12
y = 40 + 12
y = 52 <== total cost is 52 for 4 lessons