Question

HELP PLEASE!

Sam is putting money into a savings account. He starts with $550 in the savings account, and each week he adds $40.Let S represent the total amount of money in the savings account (in dollars), and let W represent the number of weeks Sam has been adding money. Write an equation relating S to W. Then use this equation to find the total amount of money in the savings account after 18 weeks.

Answer 1

one point on the line (0,550)

Slope of the line: 40

Answer 2

Well have you written an equation yet?

Answer 3

HUH?
@DanJS
i need an equation

Answer 4

you have one point and the slope, you can use point slope form for a line

S - S1 = m(W-W1)

Where m = 40, and (W1,S1) = (0,550)

Answer 5

plugging the numbers in gives

S - 550 = 40(x - 0)

Answer 6

i dont need a line
i need an equation

Answer 7

S- 550 = 40*W

S = 40*W + 550

Answer 8

and i need the amount of money in 18 weeks

Answer 9

the equation is a line

Answer 10

so when W= 18 weeks, calculate S

S = 40*W+550

Answer 11

ohhhh so the equation is S - S1 = m(W-W1)???

Answer 12

@DanJS

Answer 13

yes, that is the point-slope form of a line
if you are given a point (S1,W1) and the slope m, you can plug the values in and get the equation for the line

Answer 14

okay got it

Answer 15

so now how much money would it be in 18 weeeks?

Answer 16

Let W=18

Answer 17

S = 40*18+550

Answer 18

1270

Answer 19

the point (18,1270) is also on the line

Answer 20

@DanJS can i write the equation without brackets??

Answer 21

yeah from point slope form you get

S - 550 = 40(W - 0)

Rearranging some, you get

S = 40*W + 550

Answer 22

@DanJS hey

Answer 23

?

Answer 24

so the money in 18 weeks would be 1270 right

Answer 25

yep

Answer 26

each of these values , 0 weeks 550 dollars, and 18 weeks 1270 dollars , are just points on a line (S,W) -- (0 , 18) and (18,1270)

S = 40W+550