The water level in a glass decreases 0.4 cm each hour due to evaporation. At the beginning of the experiment, the water level is 12.6 cm. Let x represent time, in hours, elapsed since the beginning of the experiment and let y represent the water level, in centimeters.

Part A

Construct a linear function, using x and y from above, that determines the water level at a given time, in hours, after the experiment begins.

Question 2
Part B

How many hours does it take for all of the water to evaporate?

hours

walter needs to make at least 5 more cookies but no more than 40. 5 ≤ x ≤ 40

step-by-step explanation:

20 ≤ x + 15 ≤ 55

subtract 15 from all parts

20-15 ≤ x + 15-15 ≤ 55-15

5 ≤ x ≤ 40

this means how many more cookies he has to make

walter needs to make at least 5 more cookies, but no more than 40 cookies; 5 ≤ x ≤ 40

step-by-step explanation:

step 1: solve one of the equations for one of the variables. let's solve the first equation for y:

step 2: substitute that equation into the other equation, and solve for x.

step 3: substitute x = 4 x = 4 x=4 into one of the original equations, and solve for y.

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step-by-step explanation: