а) xy- 9 x - (x - 2xy) =xy-9x-x+2xy=3xy-10x
б)12 x2y - 6 xy - 24x y2=6xy*( 2x-1-4y)
в)b-c-a(c-b)= b-c-ac+ab
г)16 - 9 x2+ 4 x2=16-5x^2
Первый=2
второй=2.5
третий=3
в сумме = 7.5
b)
52-5/6= (6*52-5) /6= (312-5)/6=307/6 = 51 7/6
d)
55-2 2/5= 55 -12/5 = (55*5-12)/5=(275-12)/5=263/5= 52 3/5
l)
53 7/8 - 9/10 = (431/8 – 9/10 =(431*10-9*8) / 80 =(4310-72)/80=4238/ 80= =52 70/80=52 7/8
p)
233 3/10- 1 11/15=2333/10 - 26/15=(2333*6-26*9)/90=(13998-234)/90= =13764/90=152 42/45