Question

Y varies directly as x.if y=-5 when x =15find x when y=3

Answer 1

y=kx
-5=k(15)
-5/15=k
-1/3=k
now,
y=-1/5x
3=-1/5x
3×5=-1(x)
15=-1(x)
multiplying both sides by -1,we get
-15=x