Definite Integral [help] !!!

mckallin

hello, can anyone help me how to complete the following definite integral? Thanks!!
∫ (x^2)*sqrt(7 x + 9) dx (From 0 to 1)

Rainbow Child

Try the substitution

[tex]\sqrt{7x+9}=y[/tex]

mckallin

sorry, I still can't figure out it, can you give me some more detail? thanks a lot .

HallsofIvy

If [itex]y= \sqrt{7x+ 9}[/itex], what is dx (in terms of dy and y)? What is x in terms of y? (So you can substitute for that x².)

mckallin

I got it, thanks for help!! ^-^