1, left identical and right different is a simple memory formula for determining the position of symmetry axis in quadratic function. When the ab symbols are the same, the symmetry axis is on the left side of the Y axis; when the ab symbols are different, the symmetry axis is on the right side of the Y axis. So it's called left-right difference.

2. When the symbols of A and B are the same (i.e. a.b0), the symmetry axis is on the left side of the Y axis; Because if the symmetry axis is on the left, the symmetry axis is less than 0, that is, -b/2a0, so b/2a is greater than 0, so a and b should have the same sign.

3. When the signs of A and B are different (that is, a.b0), the symmetry axis is on the right side of the Y axis. Because the symmetry axis is on the right, the symmetry axis is greater than 0, that is, -b/2a0, so b/2a is less than 0, so the signs of A and B are different. Summarized as follows:

4. The quadratic function in mathematics, in Y = AX 2+BX+C, when the ab sign is the same, the symmetry axis is on the left side of the Y axis, and when the ab sign is different, the symmetry axis is on the right side of the Y axis. So it's called left-right difference.

5. It can be simply recorded that the left and right are the same, that is, when the symbols of A and B are the same (that is, ab0), the symmetry axis is left on the Y axis; When the signs of A and B are different (i.e. ab0), the symmetry axis is on the right side of the Y axis.