I don't know what that "6" means

, using the substitutionYou areu = f(x).( where f(x) is 9x^2 -4told= what to do- DO IT! Let u= 9x^2- 4. What is du?

Is this or ?Integrate x+2/f(x) dx where f(x) is 9x^2 -4

Think of " ". Try 3x= 2sin(u).Integrate 1/(4-9x^2)^1/2 dx

Please a step by step process is appreciated as I am horrible in integration and need help, Thank you for your help =)