0.5x + 1/5y -3.5x - 4/5 y
0.5x - 3.5x + 1/5 y - 4/5 y. Regroup f/ variable
-3.0x - 3/5 y
Answer: Line DB
Think of the two planes as pages in a book. They are joined by the spine, which is where the two planes intersect. In this case, that intersection is the line DB.
Point D is on both planes R and S. So is point B. Every point on line DB is found on both planes.
The answer will be 25 using the Pythagorean theorem.<span />
