Calculus
# First Order Differential Equations

If function $f(x)$ satisfies $\frac{df(x)}{dx}=(3x+4)(2-x) \text{ and } f(-1)=18,$ what is $f(x)?$

If $f'(x)=9x^2$ and $f(2)=31,$ what is $f(x)?$

If $f'(x)=\sin x-2\cos x, f(\pi)=9,$ what is $f(x)?$