-3/5, -6/10, -9/15,-12/20,….

⇒ -3×1/5×1, -3×2/5×2, -3×3/5×3, -3×4/5×4,………
Therefore, the next four rational numbers of this pattern would be
-3×5/5×5, -3×6/5×6, -3×7/5×7, -3×8/5×8, = -15/25, -18/30, -21/35, -24/40

Class 7 Maths Chapter 9 Exercise 9.1

for more answers vist to:
https://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-9/