Question

Aisha just received a $40 paycheck from her new job. She spends some of it buying music online and saves the rest in a bank account. Her savings is given by f(x) = 40 ­ 1.25x, where x is the number of songs she downloads at $1.25 per song.

a. Graph the function.

Answer 1

edit: f(x) = 40 - 1.25x

Answer 2

@jim_thompson5910

Answer 3

put it in y = mx+b form
f(x) also means y
we just need rearranging for the formula

Answer 4

y = -1.25x + 40

Answer 5

yup... now we just graph that... hmm..... not by hand .... with desmos online grapher

Answer 6

i have to take a pic of it to send it through online, so i gotta do it by hand lol

Answer 7

if we chose x = 0 then y = 40 and that is crazy to graph manually

Answer 8

oh wow XD good luck XD

Answer 9

lol, can u tell me what goes on the x value line and the y value so i can graph?

Answer 10

I think it's torture .... when x = 0 y = 40 so by graph paper you will have to combine sheets

Answer 11

well we can just let x = 0,1,2,3... and then solve for y
same process when x = -1,-2,-3 and then solve for y

Answer 12

i mean, when i graph this manually, the y values will be 0 to 40 and the x values will be..1 2 3 etc?

Answer 13

we can choose our x ... that's why x can be 0,1,2,3. we plug those values into the equation so we can solve for y
when x = 0
y = 1.25(0) +40
y=0+40 = 40
so
(0,40) is a point on the graph

Answer 14

when x = 1
y=1.25(1) +40 = 1.25+ 40 = 41.25
so (1,41.25)

Answer 15

that's torture to draw manually

Answer 16

hmm yea >.< lol i'll see what i can do, thanks!

Answer 17

ugh .. I forgot the negative
ok that didn't make an impact when x = 0
but it does when x = 1
so
y=-1.25+40 = 38.75
(1, 38.75)
that makes better sense.

Answer 18

damn I was half drowsy when I was doing the x = 1 xD

Answer 19

this is what im kinda confused about

Answer 20

i plot 40 on the y axis, and i gotta go down -1.25 cuz thats the slope, but what numbers do i put on the x axis

Answer 21

if your graphing by 5's... it should be uniformed..