Question

The equation of a line passing through the origin and perpendicular to the lime 7x+7y=0 is _______ a) 7x-3y+4=0 b)3x-7+4=0 c) 3x+7y=0 d)7x-3y=0​

Answer 1

Let the slope of the unknown line be m.

Slope of line AB =−

3

7

Slope of line AC =−

7

3

∠ABC=

3−7m

−7−3m

∠ACB=

7−3m

−3−7m

As the sides are equal, so should the angles.

3−7m

−7−3m

=

7−3m

−3−7m

49−9m

2

=9−49m

2

40m

2

=−40

m=∓1

Hence, the equation of the line is

y−3=−(x+3)

y+x−6=0