hwo to find the quadratic eq.represented by the table?

Question

x l -2 l -1 l 0 l 1 l 2
y l -1 l 2 l 3 l 2 l -1

Answer 1

first of all find the equation of the parabola by using these points either graphically or algebraically by finding the a,b and c in theax^2+bx+c=0
after putting it in this form maybe you can put it in the standard form
y-k=a(x-h)^2
to find the vertex,focus,axisof symmetry etc.

Answer 2

Let y = ax^2+bx+ c

now put x = 0 we get 3 = c

so y = ax^2+bx+ 3

put x = -2 and y = -1

-1 = 4a -2b + 3
and x = 2 and y = -1
-1 = 4a+2b+ 3

from the 2 b = 0 and a = -1

so y = 3-x^2

x =-1 and +1 we chek that values are correct

so y = - x^2 + 3

Mency I hope I helped you

Answer 3

If the points are exact fits on the quadratic, then use the general form of the quadratic equation:

y = ax^2 + bx^2 + c

Enter three of the pairs in the above for x and y and get three equations in three unknowns (a,b,c). Solve for them and use the fourth pair to check.