Question

Determine the values of x when f(x)=40 for the function f(x)=2(x-3)^2-8

Answer 1

Answer:

x = 3 ± $\sqrt{24}$

or

x = 3 + $\sqrt{24}$, x = 3 - $\sqrt{24}$

Step-by-step explanation:

given f(x) = 2(x - 3)^2 - 8, find when f(x) = 40

So, we plug in 40 for f(x) in the 1st equation and solve for x.  (Aim to got x on its own)

40 = 2 (x - 3)^2 - 8

+ 8          + 8

-----------------------------

48 = 2 (x - 3)^2

/2            /2

-----------------------------

24 = (x - 3)^2

square root both sides

--------------------

$\sqrt{24}$ = x - 3

x = 3 ± $\sqrt{24}$