1. According to the meaning of the question, the inclination of the straight line is 120, so the inclination of the straight line is 90. Because the straight line passes through the (2,0) point, the equation of the straight line is x=2.

2. Let the linear equation be: y = kx+b.

From the meaning of the question: 22tan α-11=15+9tan α, so tanα=2, so the slope k of the straight line L is 2, because the intercept of the straight line L on the X axis is -2, so 0 = 2 *(2)+b, so b=4.

3. Let the straight line equation be y=kx+4, because the straight line and the straight line y=3x+4 are symmetrical about y, so k=-3.

So the linear equation is y=-3x+4.

4. The inclination of line y=-(√3/3)x+5 is 150, so the inclination of line L is 30, so the slope of line L is √3/3. Let the equation of the straight line L be y = (√ 3/3) x+b.

(1) Because the straight line L passes through point P(3, -4), -4=(√3/3)*3+b, so b=-4-√3/3.

So the equation of the straight line L is y=(√3/3)x-4-√3.

(2) Because the intercept of the straight line L on the X axis is -2, so 0=(√3/3)*(-2)+b, so b=2√3/3.

So the equation of the straight line L is y=(√3/3)x+2√3/3.

(3) Because the intercept of the straight line L on the Y axis is 3, b=3.

So the equation of the straight line L is y=(√3/3)x+3.