tolong bantu ya kka nomer 10 sama 11

11. 15-6y = 4y-25
. -6y-4y = -25-15
. -10y = -40
. y = -40 : -10
. y = 4

y-5
4-5 = -1
Maaf Nomer 10 kurang tau. Semoga bermanfaat