5/9(3.6а- 3 3/5b)-3.5(4/7a-0.2b) заранее )

3 3/5 =18/5 =3.6

1)
5/9(3.6a-3.6b)=5/9 *18/5(a-b) =90/45(a-b) =2(a-b)

2) 3.5 =35/10 =7/2
0.2 =2/10 =1/5

7/2 *4/7a -7/2*1/5b =28/14a -7/10b =2a -0.7b

3) 2(a -b) -(2a -0.7b) =2a -2b -2a +0.7b = -2b +0.7b = -1.3b