Can you help me graph these parabolas?

Question

My summer packet cut off the instructions telling me how to do this part of the packet. Can you help me find the vertex, axis of symmetry, and x and y intercepts while using the completing the square method:

1. y=x^2-2x-7

2. y=4x^2-8x+2

3. y=1/2x^2+4x+8

4. y=-2x^2-4x+3

Answer 1

1. y=x^2-2x-7

y=(x-1)^2-8

Vertex (1,-8)

Axis of symmetry x=1

y-intercept y=-7

x-intercept x=1+/-sqrt(8)

2. y=4x^2-8x+2

y=4(x-1)^2-2

Vertex (1,-2)

Axis of symmetry x=1

y-intercept y=2

x-intercept x=1+/-sqrt(1/2)

3. y=1/2x^2+4x+8

y=(1/2)(x+4)^2

Vertex (-4,0)

Axis of symmetry x=-4

y-intercept y=8

x-intercept x=-4

4. y=-2x^2-4x+3

y=-2(x+1)^2+5

Vertex (-1,5)

Axis of symmetry x=-1

y-intercept y=3

x-intercept x=-1+/-sqrt(5/2)