# How do you write the quadratic equation of the graph with the given points (-3, 4), (1,0), and (-1,-2)?

Apr 16, 2015

Let's try this:
your quadratic should have the form: $y = a {x}^{2} + b x + c$ and we can try to find $a , b \mathmr{and} c$ by substituting our points in $x$ and $y$:
$4 = 9 a - 3 b + c$
$0 = a + b + c$
$- 2 = a - b + c$
I used Cramer's Rule to solve this system (although I am not sure you know about this) and I found:
$a = 1$
$b = 1$
$c = - 2$
And the equation is: $y = {x}^{2} + x - 2$