Quote (Azrad @ Nov 12 2013 10:22am)
#7
a) the minus sign on the x^2 term means it opens downward
b.) a parabola is symmetric around a vertical line through its vertex:
x = -b/2a ---> x = -(-2)/[(2)*(-1)] = 2/-2 = -1
x = -1
c) well we know the x coordinate is -1 from part b, so just plug that into the equation to get the y value:
y = -(-1)^2 - 2(-1) + 15 = -1 + 2 + 15 = 16
so the point is {-1,16}
d) at the y intercept, x = 0, so lets just plug in x = 0 into the parabola:
y = -(0)^2 - 2(0) + 15 = 15
{0,15}
e) at the x intercept(s), y = 0, so lets just plug that into the parabola:
0 = -(x)^2 - 2(x) + 15; using quadratic formula gives:
x = -5, 3
{-5,0}, {3,0}
f) heh I'll leave the graph to you, just plot the points above and connect the dots with a nice curve
how much fg do u want