How do you find an equation in standard form of the parabola passing through the points (1,1), (-1, -3), (-3, 1)?
Please see the explanation for steps leading to the answer:
There are two standard forms for a parabola:
Type 1 opens up or down:
Type 2 opens left or right:
Plot the 3 points:
The points look like they fit the first type.
Write 3 equations by substituting the 3 points into the type 1 form:
Move the coefficients in front of the variables:
Subtract equation  from equation 
Substitute 2 for b into equations  and :
Subtract equation  from equation :
Substitute 1 for a in equation :
Confirm that the equation:
The equation is