Question

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

Answer 1

You need to complete the square.

Answer 2

First factor out the negative 1

Answer 3

ok, then

Answer 4

Complete the square

Answer 5

thats what i dont know how to do

Answer 6

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.

Answer 7

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.

Answer 8

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