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

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

anonymous · Answer

@geishaology

ddcamp · Answer

b is the output when the input is 0. Since 21 is the value when x (books purchased) is 1, b can not be 21.

m is the slope, the amount that y changes when x changes. When the number of books purchased goes up by one, what does the cost of the book club go up by?