Ax+By+C=0 (where a and b are not 0 at the same time)

2; Point skew: It is known that a point (x0, y0) on a straight line and the slope k of the straight line exist, and the straight line can be expressed as

y-y0=k(x-x0)

When k does not exist, a straight line can be expressed as: x=x0.

When k is 0, a straight line can be expressed as y=y0.

3. Intercept type: inapplicable range: any straight line perpendicular to the coordinate axis and straight line passing through the origin.

Given that a straight line intersects the X axis at (a, 0) and the Y axis at (0, b), it can be expressed as

x/a+y/b= 1

4. Oblique section: y = kx+b (k ≠ 0) when k > 0, y increases with the increase of x; When k < 0, y decreases with the increase of x.

When two straight lines are parallel, K 1=K2.

When two lines are perpendicular, K 1 X K2 =-1.

5. Two-point style

X 1 is not equal to x2 y 1 is not equal to y2.

Two-point type

(y-y 1)/(y2-y 1)=(x-x 1)/(x2-x 1)

Equation of bisector

1. find the linear equation a1x+b1y+c1= 0, A2X+B2Y+C2 = 0.

2. Set any point P(x, y) on the angular bisector, and set the equation according to the basic properties of the angular bisector:

|a 1x+b 1y+c 1|/√(a 1^2+b 1^2)=|a2x+b2y+c2|/√(a2^2+b2^2)，

3. Simplify and get two linear equations, which represent two straight lines, one is the straight line where the bisector of this angle is located, and the other is the straight line where the bisector of the adjacent complementary angle of this angle is located.

4. Test: delete the bisector equation of the adjacent complementary angle and determine the straight line equation of the bisector of this angle.