Question

Find the coordinates of the vertex and the equation of the axis of symmetry of the parabola given by the equation.

y = − 1/7 x^2 + x − 3


and graph it

Answer 1

y = -1/7 x^2 + x - 3
= -1/7 (x^2 - 7x) - 3
now complete the square
y = -1/7 (x^2 -7x + (7/2)^2) - 3 + 1/7 (7/2)^2

y = -1/7 (x - 7/2)^2 - 5/4

Now you can just read off the coordinates of the vertex, no?

graph at

http://www.wolframalpha.com/input/?i=-1%2F7+x^2+%2B+x+-+3