ASAP!! HELP!!!
1) Express $\dfrac{30+19i}{4+9i}$ in the form $a + bi$, where $a$ and $b$ are real numbers.
2) For what real number $k$ does the product $(25 + ki)(3+2i)$ equal a real number?
3) What constant must we place in the box below in order to be able to factor the resulting expression into the product of two linear factors:
\[2mn - 16m - 7n + \boxed{\phantom{00}}?\]
4) How many pairs of integers $(b,c)$ satisfy the equation
\[\frac{b + 7}{b + 4} = \frac{c}{9}?\]
