GED Mathematical Reasoning TestAlgebraic Problem Solving with Graphs and FunctionsMedium
A scientist is tracking the growth of a plant. The height of the plant, h(t), in centimeters, after t weeks is modeled by the function h(t) = 0.5t^2 + 2t + 10. What is the height of the plant after 4 weeks?
- A34 cm
- B42 cm
- C26 cm
- D16 cm
Show answer & explanationAnswer & explanation
Correct answer: C. 26 cm
To find the height after 4 weeks, substitute t=4 into the function: h(4) = 0.5(4)^2 + 2(4) + 10 = 0.5(16) + 8 + 10 = 8 + 8 + 10 = 26 cm.
Why the other options are wrong
- A. This may result from calculation errors, such as squaring 2t instead of just t.
- B. This may result from calculation errors, such as adding too much or incorrect order of operations.
- D. This may result from calculation errors, such as miscalculating 0.5 * 4^2.
Evaluating a Function
Evaluating a function means substituting a given input value into the function's equation and calculating the corresponding output value.
- Replace every instance of the independent variable with the given value.
- Follow the order of operations (PEMDAS/BODMAS).
- The result is the function's output for that specific input.
Memory trick: Plug It In, Crunch The Numbers, Get The Answer.