1) 3(a+2b)-a при a+3b=1,1;
3a+6b-a;
2a+6b = 2(a+3b) = 2·1,1 = 2,2.
2) 2,4(3x+5y)-4y при 0,9x+y=2;
7,2x+12y-4y;
7,2x+8y = 8(0,9x+y) = 2·8 = 16.
3) 8(0,5a+3b)+8a при a+2b=2,5;
4a+24b+8a;
12a+24b = 12(a+2b) = 2,5·12 = 30.
4) 3(0,6m+5n)-3n при 0,3m+2n=4;
1,8m+15n-3n;
1,8m+12n = 6(0,3m+2n) = 4·6 = 24.