Given the function f(x) = -5x² - x + 20, find f(3)?

Solution:

A relation ‘f’ from a set A to a set B is said to be a function if every element of set A has one and only one image in set B.

In other words, no two distinct elements of B have the same preimage.

It is given that

f(x) = -5x² - x + 20

We have to find f(3)

f(3) = -5(3)² - 3 + 20

By further calculation

f(3) = -5(9) - 3 + 20

f(3) = -45 - 3 + 20

So we get

f(3) = -48 + 20

f(3) = -28

Therefore, f(3) is -28.

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Given the function f(x) = -5x² - x + 20, find f(3)?

Summary:

Given the function f(x) = -5x² - x + 20, f(3) is -28.