1.
11+44х - х² -4 х³=11(1+4х) - х²(1+4х)=(11-х²)(1+4х)
63mn - 28m +36m²-49n=7n(9m -7) - 4m(7-9m)=7n(9m-7)+4m(9m-7)=(7n+4m)(9m -7)
2.
15mn -2n+15m²-2m=15m(n+m) -2(n+m)=(15m-2)(n+m)
при m=2/15, n= -2
(15*2/15 - 2)( -2+2/15)=(2-2)( -2+2/15)=0*(-2+2/15)=0
3.
5 *5/9 - 1/2 * 5/9 -1/3*5 +1/2*1/3=5/9 *(5 - 1/2) -1/3 *(5 - 1/2)=(5-1/2)(5/9 - 1/3)=4 1/2 * (5/9-3/9)=9/2 * 2/9=1