write the equation y=-x^2-3x in vertex form. What is the vertex and the axis of symmetry?

Question

mertsj · Answer

You need to complete the square.

mertsj · Answer

First factor out the negative 1

anonymous · Answer

ok, then

mertsj · Answer

Complete the square

anonymous · Answer

thats what i dont know how to do

mertsj · Answer

Take 1/2 of the coefficient of x and square it.  Add that to the x^2 and x term (which is really subtracting it since there is a minus sign outside the parentheses) so then add it again.

mertsj · Answer

There is an alternate way that might be easier.  The x coordinate of the vertex is -b/2a.  Calculate that then plug it back in to find the y coordinate.  The axis of symmetry is the vertical line that goes through the vertex.

anonymous · Answer

ill try them both thanx again,,, looks like your saving my life tonight XD