Thread: Functions and relations, need help desperately!

If f(x) = 3^x find x when f(x)= 1/27

if f(x) = x^3 - 1 find f(k) as a product of factors

given f(t) = t^4 + t^2 - 5 find the value of f(b)- f(-b)

please show working need help desperately!?!

Hey takkaz.

Hint: If 1/27 = 3^(x) then by log laws, log_3(1/27) = log_3(3^x) = x. Can you find a number a such that 3^(a) = 1/27 (Hint: a will be negative).