Prove the following

Question:

If $x \phi(x)=\int_{5}^{x}\left(3 t^{2}-2 \phi^{\prime}(t)\right) d t, x>-2$, and $\phi(0)=4$ then $\phi(2)$ is

Solution:

$x \phi(x)=\int_{5}^{x} 3 t^{2}-2 \phi^{\prime}(t) d t$

$x \phi(x)=x^{3}-125-2[\phi(x)-\phi(5)]$

$x \phi(x)=x^{3}-125-2 \phi(x)-2 \phi(5)$

$\phi(0)=4 \Rightarrow \phi(5)=-\frac{133}{2}$

$\phi(x)=\frac{x^{3}+8}{x+2}$

$\phi(2)=4$

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