75-33/75+33=75-33/75+33=42/108=4/9
15-6/15×2=15-6/15+6×2=9/21
26+2/26×2=26-2/26+2×2=48/56=6/7
№1
а) ab²/c в 4*с²/ab=ab/c²;
б) 36-b²/35ab*45b²/b²-12b+36=-(b-6)(b+6)/35ab*45b²/(b-6)²=-b-6*45b²/35ab=-b-270b²-35ab=-b(1+270b)/35ab=-(1+270b)/35a;
в)(x+y)²/x²-xy*xy-y²=(x+y)²*y(x-y)/x(x-y)*5(x+y)=xy+y²/5x=y(1+y)/5.
№2 на фото.
№3 на фото.
№4 не знаю.
17+(25-х)•7=80
17+175-7х=80
-7х=80-17-175
-7х=80-192
-7х=-112
-х=-6
х=6
1) 56,31-24,246=32,064
2)32,064-15,186=16,878
3)7,3-3,87=3,43
4)3,43+0,018=3,448
5)16,878-3,448=13,43