As shown in the figure, (1) substitutes x=2 into the intersection (2,5) of the equation L 1, and similarly into the intersection of L2 (1, 1), and into the straight line y=kx+b, k+b= 1. So the straight line is y=4x-3.

(2) As shown in the triangle area formula, the base = 1-(-3/4)=5/4 and the height =5, so S= 1/2*5/4*5=25/8.

(3) The bottom (Y axis) =2- 1= 1, and the height = 1/3, so S =1/2 *1*1/3 =/kloc-.

You can also find the area by linear translation, as Gao Yi said, so I won't go into details here.