Question

If f(x)=4x^2-6

find all x such that f(x)= 106

Answer 1

50

Explanation:

Answer 2

`2\sqrt7,-2\sqrt7`

Explanation:

So we have the function:

`f(x)=4x^2-6`

And we want to find all x such that f(x) is 106. So, substitute 106 for f(x):

`106=4x^2-6`

Add 6 to both sides:

`112=4x^2`

Divide both sides by 4:

`x^2=28`

Take the square root of both sides:

`x=\pm√(28)`

Simplify the square root:

`x=\pm√(28)=\pm√(4\cdot 7)=\pm2\sqrt7`

So, those are the two values that will satisfy our requirement.

And we're done!