Question

A company sells candy bars. The table below shows the total weight of a box with 1,2,3, and 4 candy bars

Number of candy bars in box| Total weight
________________________________________
1 | 9.5
2 |15.5
3 |21.5
4 |27.5

Answer 1

@ranga

Answer 2

So what is the question?

Answer 3

I am supposed to write an algebraic rule that can be used to determine the total weight of the box for any number of candy bars.

Answer 4

Well since you add 6 each time you add a candy bar, the algebraic equation would be 3.5 + 6x = Y(Total weight of the box)

Where x is the number of candy bars. You get 3.5 by finding the Y-intercept, subtracting 6 from (1, 9.5) to get (0,3.5). The y-intercept symbolizes the weight of the box.

Answer 5

Ok, thanks

Answer 6

@jim_thompson5910

Answer 7

How would I find the Y intercept?

Answer 8

From a graph? and what 2 points would I use?

Answer 9

3.5 + 6x = y is the same as y = 6x + 3.5

That second equation is of the form y = mx+b

slope: m = 6
y-intercept: b = 3.5 which is the point (0,3.5)

Answer 10

you can use any two points you want to graph the line

Answer 11

ok, Thanks!

Answer 12

How did you come up with 3.5?

Answer 13

do you know how to find the slope m = 6 ?

Answer 14

Slope is Rise/Run right?

Answer 15

How do you find the slope?

Answer 16

using the slope formula

m = (y2 - y1)/(x2 - x1)

Answer 17

So, if I picked (1,3) and (2,3) that wouldn't work...

Answer 18

?

Answer 19

(1,3) (5,6) Won't work either

Answer 20

@zzr0ck3r

Answer 21

I can't figure this out @zzr0ck3r I picked 2 random points but they don't work

Answer 22

what is your question?

Answer 23

when he says pick pionts he does not mean pick random points, he means pick random x values plug that in to get the y value, now you have a point

Answer 24

but how did he get 3.5?

Answer 25

letting x = 0, we see y = 3.5

(0,3.5) is one point

letting x = 1 we see y = 9.5

so

(1,9.5) is another

Answer 26

How did he get 3.5 to write this equation y = 6x + 3.5

Answer 27

1 -> 9.5
2 -> 15.5
3-> 21.5

so its growing by 6 every time, so to find out what we get when x is zero (i.e. the y intercept) we take away 6 from 9.5 (because its 9.5 at 1)to get 3.5.

Answer 28

or take a point (1,9.5)

you have y=6x+b

plug in your point

9.5=6+b

b=3.5

Answer 29

but to get the point (1,9.5) you needed the equation y = 6x + 3.5

Answer 30

So I will follow your first suggestion