Question

Write an equation in y = mx + b form for the table.



# books purchased

1

2

3

4


Cost of book club

21

30

39

48



A. y = 3x + 21
B. y = 9x + 12
C. y = 5x + 21
D. y = 7x + 12

Answer 1

look at the cost of book

Answer 2

21

30

39

48

Answer 3

by what amount each are incrementing ?

Answer 4

By nine

Answer 5

so that gives us y = 9x + ___

Answer 6

for finding wat to put in that blank, you can subtract 9 from cost of 1 book.

Answer 7

___ = 21 - 9

Answer 8

12

Answer 9

great ! so the complete equation is ?