# Word problems relating 3 variable systems of equations

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##### Examples

###### Lessons

**Quadratic Equation Problem**Find the equation of the parabola, $y = ax^{2} + bx + c$, that passes through (-2, -10), (1, -4), (3, 30).

**Number Problem**The sum of the digits of a three-digit number is 16. The units digit is 2 more than the sum of the other two digits, and the tens digit is 5 more than the hundreds digit. What is the number?

**Geometry Problem**The measure of the largest angle of a triangle is 30° less than the sum of the measures of the other two angles and 9° less than 2 times the measure of the smallest angle. Find the measures of the three angles of the triangle.

**Investment Problem**Thomas has $6000 invested among a checking account paying 2% annual interest, a savings account paying 5% annual interest, and a bond paying 7% annual interest. He earns a total of $355 in annual interest and he has $2300 less invested in his savings account than in her bond. How much has he invested in each account?