15th?

Asked by smanishkumar2002 | 4th Aug, 2018, 08:34: PM

Expert Answer:

ΔABC is an isosceles with AB = AC
Consider the equations of lines AB and AC are 7x - y + 3 = 0 and x + y - 3 = 0
Solving these quations we get (0, 3)
BC is passing through (1, -10)
Slope of the line 7x - y + 3 = 0 is 7
Slope of the line x + y - 3 = 0 is -1
Let m be the slope of the line BC
angle B  = angle C
tanB = tanC
begin mathsize 16px style open vertical bar fraction numerator 7 minus straight m over denominator straight a plus 7 straight m end fraction close vertical bar equals open vertical bar fraction numerator straight m minus left parenthesis negative 1 right parenthesis over denominator 1 plus left parenthesis negative 1 right parenthesis straight m end fraction close vertical bar
Solving space this space we space get space
3 straight m squared plus 8 straight m minus 3 equals 0 space or space 8 straight m squared plus 8 equals 0
rightwards double arrow left parenthesis straight m space plus thin space 3 right parenthesis left parenthesis 3 straight m space minus space 1 right parenthesis equals 0 space or space straight m squared not equal to negative 1
Hence comma space straight m space equals space minus 3 space or space straight m space equals space 1 third
Find space equation space of space BC space when space straight m space equals space minus 3 space we space get
3 straight x space plus space straight y space minus space 7 space equals space 0
when space straight m space equals space 1 third space then space equation space of space BC
straight x space minus space 3 straight y space plus space 31 space equals space 0 end style

Answered by Sneha shidid | 6th Aug, 2018, 10:36: AM