1.a)3(x-4)-8(3+5x)=0
3x-12-24-40x=0
-37x=36
x=-36/37
б)0,5(4x-5)-1,6(5x-6)=43,1
2x-2,5-8x+9,6=43,1
-6x=36
x=-6
2. 2(5x-4y)-3(4x-y)=10x-8y-12x+3y=-2x-5y
x=-5; y=0,8
-2*(-5)-5*0,8=10-4=6
3.a)3/11(55x-66y)-1,2(6x+5y)=15x-18y-7,2x-6y=9x-25,2y
б) 4,2(1,5a-0,5)-6,5(1/13a+0,2)=6,3a-2,1-0,5a-0,13=5,8a-2,23