Question

For the function: f(x) = 21 + 2x − 5x2 Find f(3)

Answer 1

F(3)=-18

You just replace x for three for your equation and then use Ofer of operations to solve it.

So f(3)= 21+ 2(3)-5(3)^2

The exponent goes first: f(3)= 21+ 2(3)-5(9)

Next is multiplication: f(3)= 21+ 6-45

Now add: f(3)= 27-45

Finally subtract: f(3)= -18

Hope this helps!