Given the function f(x)=2(x+6), find x if f(x)=22

Answer 1

Contrast f(x) = 22 versus f(22) -- the former means that the output is going to be 22, while the latter means that the x-value (AKA the input) is going to be 22.

So this means we have the following:

22 = 2(x + 6)

Divide by 2:

²² / ₂ = ^{2(x + 6)} / ₂

11 = x + 6

Subtract 6 from both sides:

11 - 6 = x + 6 - 6

5 = x

Another way to solve would be to distribute first:

22 = 2(x + 6)

22 = 2x + 12

Subtract 12:

22 - 12 = 2x - 12

10 = 2x

Divide by 2:

10 / 2 = 2x / 2

5 = x

Answer 2

If f(x)=22 then that means we can set the equation 2(x+6) equal to 22. Let's do that:

22 = 2(x+6)

Great! Now we just need to solve for x. We can divide both sides by 2 to get:

11 = x+6

Now we subtract 6 from both sides to get:

5 = x

Switch those 2 around and we have our answer!

x = 5