### Home > A2C > Chapter 7 > Lesson 7.1.5 > Problem 7-80

7-80.

Find an equation for the parabola that passes through the points (−1, 10), (0, 5), and (2, 7). 7-80 HW eTool (Desmos). Homework Help ✎

Create a system of three equations with three variables using the points and the equation *y* = *ax*^{2} + *bx* + *c*.

*a* − *b* + *c* = 10

*c* = 5

4*a* + 2*b* + *c* = 7

Substitute the value for *c* into the first and third equations to simplify.

You now have a system of two equations with two variables to solve.

*y* = 2*x*^{2} − 3*x* + 5

Use the eTool below to check your solution graphically.

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