Question

Determine the value of k so that the following system has an infinite number of solutions

10x+ky= -8
-15x-6y= 12
Please help.

Answer 1

k=4

Explanation:

remove x:

10x.(-3) + ky.(-3)=-8.(-3) (1)

-15x.2 - 6y.2 = 12.2 (2)

(1) - (2) => -3ky+12y = 0

<=> (12-3k)y = 0

so that y has infinitely many solutions then

12-3k = 0 => k=4