Find the vertices of triangle which sides are on the lines 2x+y-3=0; x-y-6=0; -2x+y-5=0?

Expert Answers info

justaguide eNotes educator | Certified Educator

calendarEducator since 2010

write12,544 answers

starTop subjects are Math, Science, and Business

The vertexes of the triangle are at the points of intersection of each pair of the three lines:

2x+y-3=0 ...(1)

x-y-6=0 ...(2)

-2x+y-5=0 ...(3)

The point of intersection of (1) and (2) can be determined by substituting x = y + 6 from (2) in (1)

=> 2(y + 6) + y - 3 = 0

=> 2y + 12 + y - 3 = 0

=> 3y = -9

=> y = -3

x = 3

One of the vertexes is (3, -3)

The point...

(The entire section contains 2 answers and 185 words.)

Unlock This Answer Now


check Approved by eNotes Editorial

samhouston eNotes educator | Certified Educator

calendarEducator since 2011

write244 answers

starTop subjects are Math, Science, and Literature

check Approved by eNotes Editorial


giorgiana1976 | Student

To determine the vertices of the triangle whose sides are along the given lines, we'll have to determine the intercepting points of these lines.

We'll determine the intercepting point of the lines 2x+y-3=0 and x-y-6=0.

We'll solve the system of equations using elimination. We'll add the equations:

2x + y - 3 + x - y - 6 = 0

3x - 9 = 0

3x = 9 => x = 3

3 - y - 6 = 0 => -y = 6 - 3

y = -3

The first intercepting point and the 1st vertex  of the triangle is the pair (3 ; -3).

We'll determine the next intercepting point of the lines x-y-6=0; -2x+y-5=0.

We'll add the equations:

x - y - 6 - 2x + y - 5 = 0

-x - 11 = 0 => x = -11

-11 - y - 6 = 0

y = -17

The 2nd intercepting point and the 2nd vertex  of the triangle is the pair (-11 ; -17).

We'll determine the 3d intercepting point of the lines 2x+y-3=0; -2x+y-5=0.

We'll add the equations:

2x + y - 3 - 2x + y - 5 = 0

2y - 8 = 0

2y = 8 => y = 4

2x + 4 - 3 = 0

2x + 1 = 0

x = -1/2

The 3rd intercepting point and the 3rd vertex  of the triangle is the pair (-1/2 ; 4).

The vertices of triangle are represented by the following pairs: (3 ; -3) ; (-11 ; -17) ; (-1/2 ; 4).

check Approved by eNotes Editorial