A linear model gives an output from an input using a rate and a starting value. If a question gives a time and asks for a depth, substitute the time into the rule, then evaluate it in Desmos. The starting value is added once, not multiplied by the time.
Hints
- Hint 1
An input is the number you put into a rule. Here, time is the input and depth is the output. Which letter should you replace to find the depth at the given time?
- Hint 2
In a linear model, the number attached to time is multiplied by the time. The number added afterward is the starting depth. Keep those two jobs separate when you substitute.
Step-by-step
Substitute the time and evaluate
Step 1Put the time into the rule
The 10 seconds is the input, the number you put into the rule. Since stands for time, replace with :
The is the starting depth, so it stays added once.
- Step 2
Find the depth
Type , then in Desmos. It shows . So 10 seconds after the faucet is turned on, the water is centimeters deep. Choice C.