Question 145·Easy·Nonlinear Functions
The function is defined by . What is the value of ?
For questions asking for a function value like , immediately rewrite the function with parentheses around the input wherever appears (for example, ). Then simplify in order: first exponents, then multiplications, then additions/subtractions, being especially careful with negative signs and double negatives. Working step by step avoids common sign and arithmetic errors and lets you answer quickly and accurately.
Hints
Use the definition of the function
You are given . To find , think about what you should do with in that formula.
Be careful with negatives
When you plug in for , write it in parentheses: . Pay attention to the square on and to the minus sign in front of .
Simplify step by step
First simplify , then do the multiplications, and only then add the three resulting numbers together.
Desmos Guide
Evaluate the function in Desmos
In one expression line, type 2(-1)^2 - 3(-1) + 4 exactly as written. Let Desmos simplify the expression, and read off the final numeric value it displays; that is the value of .
Step-by-step Explanation
Substitute into the function
The function is defined as .
To find , replace every with :
Simplify powers and products
First, simplify :
- because a negative times a negative is positive.
Now substitute that in:
Next, multiply:
- (negative times negative is positive)
So we have:
Add the terms to find the final value
Now add the three numbers:
So the value of the function at is
This matches answer choice D.