What is the equation of the straight line which passes through the point of intersection of the straight lines x + 2y = 5 and 3x + 7y = 17 and is perpendicular to the straight line 3x + 4y = 10?

What is the equation of the straight line which passes through the point of intersection of the straight lines x + 2y = 5 and 3x + 7y = 17 and is perpendicular to the straight line 3x + 4y = 10? Correct Answer 4x – 3y + 2 = 0

Concept:

  • When two lines are perpendicular, the product of their slope is -1. If m is the slope of a line, then the slope of a line perpendicular to it is -1/m.
  • Equation of line is (y – y1) = m(x – x1)

 

Calculation:

x + 2y = 5                                 …. (1)

3x + 7y = 17                             …. (2)  

Solving equation 1 and 2, we get

x = 1 and y = 2

Point of intersection: (x, y) = (x1, y1) = (1, 2)

Let slope of the straight line 3x + 4y = 10 is m1,

∴ Slope (m1) = -3/4

We know that when two lines are perpendicular, the product of their slope is -1.

Slope of perpendicular line = -1/m1 = 4/3 = m

Equation of line: (y – y1) = m(x – x1)

⇒ y – 2 = 4/3 (x – 1)

⇒ 3y – 6 = 4x – 4

∴ 4x – 3y + 2 = 0

Related Questions

How far is point 'R' from Point 'T'? Statement (I): Point 'R' is 5 metres to the north of point 'M'. Point 'U' is 4 metres to the east of point 'R'. Point 'T' is to the west of point 'R' such that points 'U' 'R' and 'T' form a straight line of  metres. Statement (II): Point 'Z' is metres to the south of point 'T'. Point 'U' is  metres to the east of point 'T'. Point 'M' is  metres to the east of point 'Z'. Point 'R' is  metres to the north of point 'M'. Point 'R' lies on the line formed by joining points 'T' and 'U'.