Question

Fine the ratio in which line formed by joining (-1,1) and (5,7) is divoded by the line x+u=4.

Answer 1

using section formula mx2+nx1/m+n and my2+ny1/ m+n, taking the ratios m/ n = k/1
where m=k ,n=1
k:1

solve it than put in the equaton

hope you understand

Answer 2

Let ratio be k:1

Now by section formula:

=m1x2+m2x1/m1+m2

m1=k, m2=1 ,x1=-1 , x2=5

So by formula

k×5+1×-1/k+1=x

5k-1/k+1=x

Now again by section formula

m1u2+ m2u1 /m1+m2

m1=k, m2=1, u1=1,u2=7

So by formula

k×7+1×1/k+1=u

7k+1/k+1=u

Now x+u=4 (given)

Putting value of x and u

(5k-1/k+1)+(7k+1/k+1)=4

12k/k+1=4

12k=4k+4

12k-4k=4

8k=4

k=1/2