52(5/11 + 6/11) = 52 * 1 = 52
1/2 * ((45 + 23) / 11) = 1/2 * 22 /11 = 2 * 1/2 = 1
12/19((23 - 4) / 15) = 12/19 * 19/15 = 12 / 15 = 3/4 = 0.75
А) 4 дм2=(4*100)см2 = 400см2
<span>б) 6 м2=(6*100)дм2 = 600дм2 </span>
1) NP=x-3, PK=2.5x, MK=2.5x+3
2) x+(x-3)+2.5x+(2.5x+3)=14
3) 7x=14, x=MN=2 -ответ