158. Find $x$ and $y$ from the equality:

a) $3 y + 5 x i = 15 - 7 i$; 
b) $(2 x + 3 y) + (x - y) i = 7 + 6 i$.
Solution. a) According to the condition of equality of complex numbers, we have $3 y=15, 5 x=-7$. From this, $x=-7 / 5, y=5$.

b) From the condition of equality of complex numbers, it follows that

$$
\left\{\begin{array}{r}
2 x+3 y=7 \\
x-y=6
\end{array}\right.
$$

Multiplying the second equation by 3 and adding the result to the first equation, we get $5 x=25$, i.e., $x=5$. Substituting this value into the second equation: $5-y=6$, from which $y=-1$. Thus, we get the answer: $x=5$, $y=-1$.

159-164. Find the values of $x$ and $y$ from the equalities: