Answer
$\begin{cases} x+y\leq15000 \\ x\geq2000 \\ y\geq 3x\\ x\geq0 \\y\geq0 \end{cases}$
See graph and explanations.
Work Step by Step
Step 1. Assume the amount in dollars in the high risk account is $x$ and the amount in the low risk account is $y$
Step 2. Based on the given conditions, we can write the inequalities as
$\begin{cases} x+y\leq15000 \\ x\geq2000 \\ y\geq 3x\\ x\geq0 \\y\geq0 \end{cases}$
Step 3. Graph the above inequalities and we can find the solution region as shown in the triangular region in the figure where the values of each investment can be identified.