Question

OPEN RESPONSE: Marisa drank one cup of milk and ate x small vanilla cookies for a snack. The linear equation below represents y, the total number of calories in Marisa's snack.

y= 12x + 120

a. what is the y-intercept represented by this equation?
b.explain what the y-intercept tells us about Marisa's snack.
c. what is the slop of the line represented by this equation?
d.explain what is the slope tells us about Marisa's snack.
e. if Marisa eats 9 small vanilla cookies, what is the total number of calories in her snack? show or explain how you got answer?

Answer 1

Do you know what y-intercept means?

Answer 2

i think its the point where it crosses over the y axis

Answer 3

Yes. So, when does this line cross the y axsis. (Hint: it crosses the y axis when x is equal to zero.)

Answer 4

im really bad at graphing, so if its 12x does it go up 12 over 1?

Answer 5

and when its 120 you start at 120 on the x axis?

Answer 6

You don't have to grph it. You can set x equal to zer0. What does y equal when x is zero?

Answer 7

And yes if it is 12 x it goes up 12 and over 1 and has a positive slope

Answer 8

-120=0?

Answer 9

or y= 120

Answer 10

yes so the y intercept is 120. HINT: 120 was in the equation right?

Answer 11

yes it was

Answer 12

So when you have to identify the y intercept again, just look for the +(what ever number) and there is your y intercept

Answer 13

is its 120?

Answer 14

yes! :) Good Job!

Answer 15

ok so part b?

Answer 16

So, this is a little trickier. We know that x is the amount of cookies she ate right? And y is the total amount of calories she ate. So the only things we don't have represented in the equation are the amount of calories in the milk and the amount of calories in the cookies. So, which number in the equation do you think represents the glass of milk and the calories in the cookies?