Answer:
Solution Given:
let ABC be an equilateral triangle with the vertex A(2,-1) and slope =-1.
and
∡ABC=∡BAC=∡ACB=60°
slope of BC
we have
=60°
Slope of AB=
now
we have
angle between two lines is
now substituting value
tan 60°= ±
doing criss-cross multiplication;
=±(1+a)
taking positive
a=
taking negative
a=
Equation of a line when a =
and passing through (2,-1),we have
y+1=
(x-2)
y=
-1
is a first side equation of line.
again
Equation of a line when a =
and passing through (2,-1),we have
y+1=
(x-2)
y+1=
y=
is another equation of line.