Quadratic Graphs
The general form of a quadratic is "y = ax2 + bx + c". For graphing, the leading coefficient "a" indicates how "fat" or "skinny" the parabola will be.
For | a | > 1 (such as a = 3 or a = –4), the parabola will be "skinny", because it grows more quickly (three times as fast or four times as fast, respectively, in the case of our sample values of a). For
| a | < 1 (such as a = 1/3 or a = –1/4 ), the parabola will be "fat", because it grows more slowly (one-third as fast or one-fourth as fast, respectively, in the examples). Also, if a is negative, then the parabola is upside-down.
Straight line graphs
horizontal and vertical lines: "x=a" and "y=a"
x=a is a vertical line through "a" on the x-axis
y=a isa horizontal line through "a" on the y-axis
Remember:
the y-axis is also the line x=0, the x-axis is also the line y=0
the main diagonals: "y=x" and "y=-x"
y=x is the main diagonal that goes UPHILL from left to right.
y=-x is the main diagonal that goes DOWNHILL from left to right.
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