What is the value of x?

Question

What is the value of x when f(x^2)=g(4x) if f(x)=4x-1 and g(x)=7+x?

 

Answer 1

f(x²) = g(4x)

 

4x²-1 = 7+4x

 

4x²-4x-1-7 = 0

 

4x²-4x-8 = 0

 

4(x²-x-2) = 0

 

4(x+1)(x-2) = 0

 

x = -1 , x = 2