1) 6(3х+5у)+7х-5у = 18х+30у+7х-5у = 25х+25у = 25(х+у)
25*3=75
2) 3(28а+b)-73a+8b = 84a+3b-73a+8b = 11a+11b = 11(a+b)
11*7 = 77
3) 3m+35n+8(3m-n) = 3m+35n+24m-8n = 27m+27n = 27(m+n)
27*4 = 108
405/7 = 57, ...
ОТвет : целая часть 57
0.5*1.3=0.65
1.54-0.65=0.89