What is the axis of symmetry and vertex given the equation, y=2x^2-12x+21

y = 2x² - 12x + 21 = 2(x² + 6x) + 21.

Using the complet the square method, you get:

2(x² + 6x) + 21 = 2(x² + 6x + 9) - 2*9 + 21 = 2(x + 3)² + 3.

So the axis of symmetry is: x = -3.

The vertex is: (-3, 3)

2(x + 3)² + 3

Explanation: Axis of symmetry: x = -3 Vertex: (-3, 3)

-3

step-by-step explanation:

a drawing really does here:

so i draw the horizontal line y=2 and the vertical line x=-2 at this intersection i put b (this is where my right angle is going to be).   so point b is at (-2,2).   point a is 5 units long and is also on y=2 so this point has to be (3,2) or (-7,2) -doesn't matter i will go with (3,2).

now we know c is at (-2,y) we don't know the y yet bet we know that c is on x=-2.

we have the area of the triangle is .5bh=12.5

we know the base length is 5 (ab)

we have the height is (2-y) if you look at your

plug in

.5(5)(2-y)=12.5

solve for y to get the y-coordinate for c

2.5(2-y)=12.5

divide both sides by 2.5 giving:

2-y=5

now subtract 2 on both sides

-y=3

y=-3