Question 165604
the vertex form of the parabola equation is y=a(x-h)^2+k, where (h,k) is the vertex
__ the axis of symmetry goes through the vertex


A. substituting __ 5=a(2-3)^2+k __ 5=a+k
__ substituting __ -25=a(-1-3)^2+k __ -25=16a+k


subtracting the equations __ -25-5=16a+k-a-k __ -30=15a __ -2=a


substituting __ 5=(-2)+k __ 7=k


y=-2(x-3)^2+7



B.the points (-3,2) and (1,2) have the same y value, so the axis of symmetry is midway between them __ x=-1


substituting __ 2=a(-3+1)^2+k __ 2=4a+k


substituting __ 8=a(-2+1)^2+k __ 8=a+k


subtracting the equations __ 2-8=4a+k-a-k __ -6=3a __ -2=a


substituting __ 8=(-2)+k __ 10=k


y=-2(x+1)^2+10