Question

find the values of k for which the pair of linear equations x+5y=10 and 3x+ky+15=0 has unique solution​

Answer 1

Answer:

x+5y=10 ....................(i)

finding the value of x from equation (i)

x=10-5y

putting the value of x in equation (ii)

3(10-5y)+ky+15=0

30-15y +ky+15=0

15-15y+ky=0

15-k+15y+ky=0

1(15-k) y(15-k)=0

(1+y) (15-k) =0

y= -1

-k=-15 k=15