This week, we learned how to find an equation of a function using the vertex and one point on the line. We then were about to put the equation into standard form.
Example 1:
Vertex= (3,-4)
Point= (4,1)
y=a(x-3)^2-4
*note: the vertex is put into the equation The x value, 3 is made negative and put into the equation with the 4 stays negative.
Next, input the point we were given into the x and y spots in the equation, then solve for a.
(1)=a(4-3)^2-4
1=a-4
5=a
Then take your a value and complete the equation.
y=5(x-3)^2-4
Then to put it into general form, we must expand the equation.
y=5(x-3)(x-3)-4
y=(5x-15)(x-3)-4
y=5x^2-15x-15x+45-4
y=5x^2-30x+41
Example 2:
Vertex=(7,-6)
Point= (9,-4)
y=a(x-7)^2-6
-4=a(9-7)^2-6
-4=a4-6
2=a4
1/2=a
y=1/2(x-7)^2-6
=1/2(x-7)(x-7)-6
=(1/2x-7/2)(x/1-7/1)-6
=1/14x^2-7/2x-7/2x+49/2-6
=1/14x^2-14/2x-37/2
y=1/14x^2-7x-37/2