3.8а+7.7+1.7b++2.5a+11.2+4.6b= 6.3a+6.3b+18.9=6.3(a+b+3)
при a+b+3=10 ⇒ 6.3 ×10=63
2 2/3 (1 1/2 a - 2 1/4 ) + 1 1/5 (2 1/2a - 5/6 ) =
= 8/3 ( 3/2 a - 9/4 )+ 6/5 * ( 5/2 a -5/6)=
= 4a-6+3a-1= 7a-7= 7(a-1)
7x-13=15
7x=15+13
x= 28:7
х=4
х/3 -2 = (х-46) /18
х/3 - (х-46)/18 - 2=0
6х-(х-46) - 2*18=0
6х-х+46-36=0
5х+10=0
5х=-10
х=-2
проверим:
-2/3 -2 = (-2-46)/18
- 2 2/3 = -2 12/18
-2 2/3 = -2 2/3