GED Mathematical Reasoning TestAlgebraic Problem Solving with Expressions and EquationsEasy
A botanist is tracking the growth of a special type of vine. The length of the vine, L, in centimeters, after 'd' days is modeled by the function L(d) = 2d^2 + 5d + 10. What is the length of the vine after 3 days?
- A43 cm
- B31 cm
- C29 cm
- D53 cm
Show answer & explanationAnswer & explanation
Correct answer: A. 43 cm
To find the length after 3 days, substitute d = 3 into the function L(d) = 2d^2 + 5d + 10. This results in L(3) = 2(3)^2 + 5(3) + 10 = 2(9) + 15 + 10 = 18 + 15 + 10 = 43.
Why the other options are wrong
- B. This results from a calculation error, possibly 2*3 + 5*3 + 10, not squaring d.
- C. This results from a calculation error, possibly 2*3 + 5*3 + 10 = 6 + 15 + 10 = 31, not squaring d.
- D. This results from a calculation error, possibly 2*(3+5)*3 + 10, or other incorrect order of operations.
Evaluating Functions
Substituting a specific value for the input variable into a function's rule to find the corresponding output value.
- Replace variable with given value.
- Follow order of operations (PEMDAS).
- Output is the function's value at that input.
Memory trick: Input In, Output Out: Plug it in, then compute!