Question

Let f(x) = 22 - 2x.Evaluate f(-2) =Solve f(x) = -1.

Answer 1

Question:

Solution:

Consider the following function:

`f(x)=x^2-2x`

then:

`f(-2)=(-2)^2-2(-2)\text{ = 4 +4 = 8}`

thus,

`f(-2)=\text{ 8}`

now, if f(x)=-1 this is equivalent to say:

`f(x)=x^2-2x\text{ = -1}`

that is:

`x^2-2x\text{ = -1}`

this is equivalent to:

`x^2-2x\text{ +1}=0`

now, solving this equation using the quadratic equation:

where a = 1, b = -2 and c= 1, we get:

`x\text{ = }1`

so that, we can conclude that the correct answers are:

`f(-2)=\text{ 8}`

and

`x\text{ = }1`