let's say the amounts were "a" and "b", at 12% and 9% respectively
so... the total amount of those two, is $9500, since that was the total
amount invested, thus
a + b = 9500
now, 12% of a plus 9% of b, yielded $1032
12% of a is 12/100 * a or 0.12a
9% of b is 9/100 * b or 0.09b
thus
0.12a + 0.09b = 1032
[tex]\bf \begin{cases}
a+b=9500\to b=\boxed{9500-a}\\
0.12a + 0.09b = 1032\\
--------------\\
thus
\\\\
0.12a + 0.09(\boxed{9500-a}) = 1032
\end{cases}[/tex]
solve for "a", to see how much was invested at 12%,
what about "b"? well, b = 9,500 - a
