A known input inside a function, such as , calls for function evaluation: put in place of every in the rule. For a negative input, use parentheses so the square applies to the whole number. On the SAT, you can define the function in Desmos, then enter the requested value on a new line.
Hints
- Hint 1
In function notation, the number inside the parentheses is the input. To find , replace every in the rule with . What expression does that give you?
- Hint 2
A square applies to the whole number in parentheses: , but . The product is positive, too. Check both signs before reading the output.
Step-by-step
Substitute, then evaluate in Desmos
Step 1Replace the input in the rule
means put in for every in the given rule. Keep the negative input in parentheses so the square applies to all of :
- Step 2
Read the function's output
Type to define the function, then type on the next line. Desmos shows . The two sign checks are and , so the value of is . Grid in 10.