Odpowiedzi

2010-03-10T15:39:41+01:00
X-jeden bok
x+4-drugi bok
obw=20
obw=2x+2(x+4)
20=2x+2(x+4)
20=4x+8
4x=12
x=3
x+4=3+4=7
P=3*7=21
2010-03-10T15:40:25+01:00
X+x+x-4+x-4=20 pole = a*b = 7* 3 = 21cm²
4x=20+4+4
4x=28/4
x=7
7-4=3