Step-by-step explanation:





Answer:
x = 6
Step-by-step explanation:
the smaller triangle is 3 times smaller than the big one
We invested $7000 invested in two accounts, we don't know how much exactly is in each account, therefore we will assign variables to these amounts. The amount invested in the "8%" account is "x", while the other one is "y". The sum of these two numbers must be equal to $7000, therefore:

The sum of interest of each account should be equal to 580, therefore:

We need to solve the system in order to determine the values.

Now we can replace the value of "x" in the first equation to determine the value of "y".

The values are 6500 in the 8% account and 500 in the 12% account.
From the graph of a quadratic equation, you can find:
The roots. These are the points where the graph crosses the x-axis, and is the solution of the quadratic equation when y=0. Usually, there are either two or zero.
The coefficient of the leading term. In the quadratic equation y= ax^2 + bx + c,
the parabola points upward if a is positive, and downward if a is negative.
The vertex. You can find the vertex, or where the two sides of the parabola meet, by looking at the graph.