A )
−
1
21
+
−
1
28
=
−
4
84
+
−
3
84
=
−
7
84
=
−
1
12

start with a line segment pq that we will copy. mark a point r that will be one endpoint of the new line segment. set the compasses' point on the point p of the line segment to be copied. adjust the compasses' width to the point q. the compasses' width is now equal to the length of the line segment pq.

step-by-step explanation:

add 8+12 to get a simplified answer of 12r-20

the solution, from the graphing of the two lines, is (3,2), i.e., x = 3, y = 2.

x:       y:  

-1         4

0         4

1         6

2         18

3         20