Let the function f be defined by f(x) = √2x. If f(c) = 4, what is the value of c?

Please explain...I'm writing the PSAT in an hour.

Let the function f be defined by f(x) = √2x. If f(c) = 4, what is the value of c?
If f(x) = √2x then f(c) = √2c





So if f(c) = 4 then √2c = 4





There are 2 ways I can read your equation.





√2c = (√2)c or √2c = √(2c)





(√2)c = 4 -%26gt; c = 4/√2 = 4√2/2 = 2√2





√(2c) = 4 -%26gt; 2c = 16 --%26gt; c=8





Hope that helps!
Reply:sqrt(2x)=4


2x = 16


x = 8


so f(8) = 4





if it is sqrt(2)*x = 4


then x = 4/sqrt(2) = 2sqrt(2)
Reply:√2c = 4


2c = 16


c = 8
Reply:I think you substitute x for 4.