Cannot sort: Given that f(x) = 3x+1 and g(x) = x^2 solve fg(x) = gf(x)

[Lynxbci]

Given that f(x) = 3x+1 and g(x) = x^2

solve fg(x) = gf(x)

Fg(x) 3x^2+1
gf(x) 9x^2 +6x+1

but cannot solve, help please?

thanks, this is a GCSE level question for 15 year old, should be straight forward but I cannot solve it

 

[Deleted member 4993]

Given that f(x) = 3x+1 and g(x) = x^2

solve fg(x) = gf(x)

Fg(x) = 3x^2+1
gf(x) = 9x^2 +6x+1

but cannot solve, help please?

thanks

What do you get when you apply the condition:

fg(x) = gf(x)

3x^2+1 = 9x^2 +6x+1

Simplify and continue......

 

[Lynxbci]

What do you get when you apply the condition:

fg(x) = gf(x)

3x^2+1 = 9x^2 +6x+1

Simplify and continue......

this I have already, but I do not seem to be able to simplify?
it does not seem to equate

 

[Deleted member 4993]

this I have already, but I do not seem to be able to simplify?
it does not seem to equate

3x^2+1 = 9x^2 +6x+1

0 = (9x^2 +6x+1) - (3x^2+1)

continue....