3a + 6b = a + 4b

Answer 1

combine like terms

3a-a =4b -6b

2a =-2b

divide by 2

a =-b

check the answer, plug -b in place of a in the original equatin

3(-b) +6b = 4b +(-b)

-3b + 6b = 4b -b

(6-3)b = (4-1)b

3b = 3b

a=-b or b=-a