Second,? The formula for finding the symmetry axis: X=-(b/2a)?
Third,? Usually used to solve analytic expressions:
1. Intersection? y=a(x-x 1)(x-x2)？ [only applicable to a (x 1, 0) and? B's parabola (x2, 0)]?
2.？ Vertex? y = a(x+h)& amp； sup2+k？ Its vertex is (-h, k)
Fourth,? Root-seeking? draw
How do verbs (short for verb) use the intersection with the X axis? δ=b^2-4ac，
δ> 0, where the image intersects the X axis at two points:
([-b-√δ]/2a, 0) and ([-b+√δ]/2a, 0);
Δ = 0, the image intersects the x axis at one point:
(-b/2a，0)；
δ < 0, the image has no intersection with the X axis;
Six? Monotonicity (increase or decrease)
a>0？ What time? Open your mouth? The left side of symmetry axis is monotonically decreasing? Symmetry axis increases to the right
a