3( m - n)^2 + 4mn = 3(m^2 - 2mn + n^2) - 4mn = 3m^2 - 6mn + 3n^2 - 4mn=
= 3m^2 - 10mn + 3n^2
<span>100% - начальная</span>
<span>1.
</span>100+р
<span>2.
</span>50+р
<span>3.
</span>(50+р)*2=100+2р
<span>4.
</span>100+2р-р=93,75
р=6,25
А/а(а+б):а(а+б)(а-б)=(а-б)/а
0,7+2,1= 2,8
2,8:2,1=1 целая 7/21