Question

You have been asked to find the value of f(-5) for the function

f(x)=3x2 -2x+5

Which of the following options is NOT a possible way to evaluate that function and find the correct answer?

Substitute (-5) wherever there is an x and solve using a calculator

Graph the equation and find the y-value of the ordered pair when x=-5

See what x is when y=-5

Graph the equation and look at the table to find the y-value when x=-5

Answer 1

Answer: The option that is NOT a possible way to evaluate the function and find the correct answer is

See what x is when y=-5

Step-by-step explanation:

In the function f(x) = 3x^2 - 2x + 5, x is the input variable and y is the output variable. To find the value of f(-5), we need to substitute -5 wherever there is an x in the function and then solve the resulting expression. This is the first option.

The second and forth options are also correct ways to evaluate the function, they involve graphing the equation and finding the y-value of the ordered pair when x=-5.

But the third option is not the correct way, because it is asking to find x when y=-5, but in the given function the y is unknown, so it is not possible to find x when y=-5.

Step-by-step explanation:

Answer 2

The answer is “see what x is when y=-5” as the number in f(x) is the number that you substitute for x and use to solve the equation. Therefore, it wouldn’t make sense to substitute y with -5. If you wanted to find -5, you would substitute x for -5 and solve the equation