5+3=8 частей
2000:8=250г одна чась
250*5=1кг 250г = 1,25кгмедь
250*3=750г=0,75кг цинк
S=22,75
P=2LM+2LK
20=13+2LK
7=2LK
LK=3.5
S=LK*LM=3.5*6.5=22.75
5.387.284.367+21.542.357.285+3.070.358.347 = 29. 999. 999. 999
278.504.247.961+33.869.029.453+87.696.632.596= 149.416.086.840
A) x^2+12x+36-(x^2-25)=73
x^2+12x+36-x^2+25=73
12x+61=73
12x=12
X=1
B)x^2+4x+4-x^2=9
4x+4=9
4x=9-4
4x=5
X=4/5