(11х+у)²=121x²+22xy+y²
(3с-d)²=9c²-6cd+d²
(-m-2b)²==m²+4mb+4b²
(-2a+5c)²=25c²-20ac+4a²
2,01²=(2+0.01)²=2²+2*2*0.01+0.01²=4+0.04+0.0001=4.0401
1,97²=(2-0.03)²=2²-2*2*0.03+0.03²=4-0.12+0.0009=3.8809
3,98²=(4-0.02)=4²-2*4*0.02+0.02²=16-0.16+0.0004=15.8404
(a+2b)²-3ab=a²+4ab+4b²-3ab=a²+ab+4b²
(5x-y)²+10xy=25x²-10xy+y²+10xy=25x²+y²
(-0,5c+d)²+cd=d²-cd+0.25c²+cd=d²+0.25c²
(-x-y)²-2xy=x²+2xy+y²-2xy=x²+y²
y²-18y+81=(y-9)²
p²-1,2p+0,36=(p-0.6)²
36m²+n²+12mn=(6m+n)²
-12ab+9a²+4b²=(3a-2b)²