# Math Help - Finding the upper limit of the integral

1. ## Finding the upper limit of the integral

Find the numbers b such that the average value of f(x) = 2+6x-3x^2 on the interval [0,b] is equal to 3

I am stuck at b^2(3-b)=b and don't know what to do. Or I am doing something wrong ?

2. Just solve $b^3-3b^2+b=0.$

3. Oh!!! Thanks I didnt realize that

4. So my answer is coming in decimals,is it ok...?

5. Originally Posted by racewithferrari
So my answer is coming in decimals,is it ok...?
I get $b=\frac{3\pm\sqrt{5}}{2}$.