2)Представьте в виде многочлена стандартного вида: (5x - y)² - (y + 5x)² 3)Вычислите с...

2) $(5x-y)^{2} - (y+5x)^{2} = 25x^{2}-10xy+ y^{2} - y^{2} -10xy-25 x^{2} = -20xy$
3) $7.2^{2} = (7+0.2)^{2} = 49+2.8+0.04=51.84$
   $18^{3} = (20-2)^{3}=8000 - 2400+ 240-8=5832$
   $6.8^{2} = (7-0.2)^{2} = 49-2.8+0.04=46.24$
   $31^{3} = (30+1)^{3}= 27000+2700+90+1= 29791$
4) $(x+4m)^{2} = x^{2} +8xm+ m^{2}$
   $(3a-4)^{3} = 27 a^{3}-108 a^{2} +144a - 64$
   $( p^{2}+2 q^{2}r) ^{2} = p^{4} +4 p^{2} q^{2}r+4 q^{4} r^{2}$
   $(x-6m)^{2}= x^{2} -12xm+36 m^{2}$
   $(5a+2)^{3} = 125 a^{3} +150 a^{2} +60a-8$
   $( p^{3}q - 3 r^{2} ) ^{3} = p^{9} q^{3}-9 p^{6}q2 r^{2} + 27 p^{3}q r^{2} -27 r^{6}$