3)20%x240= 20/100x240=2/10x240=2x240/10=2x24=48
240-48=198 lei
4)Centrul de greutate se gaseste la intersectia medianelor => G apartine AM
=>AG=AMx2/3=18x2/3=36/3=12 cm
=>GM=AMx1/3=18x1/3=18/3=6 cm
5)In triunghiul ABM=>Teorema Pitagora=>[tex]AM ^{2} =AB^{2}-BM^{2}=6^{2}-4^{2}=36-16=\ \textgreater \ AM^{2}=10[/tex] [tex]=\ \textgreater \ AM=2\sqrt{5} [/tex]
6)[tex]0,(8)= \frac{8+1}{9} = \frac{8}{9} ,
\frac{2a}{3b} = \frac{8}{9}
[/tex]
2a·9=3b·8(vom imparti prin 6)
18a=24b
3a=4b
a+b=56
a=56-b
3·(56-b)=4b
168-3b=4b
7b=168=>b=168/7=24
24+a=56=>a=56-24=32
7)a-b=40
a:b=4rest1
a=4b+1
4b+1-b=40
3b+1=40=>3b=40-1=39=>b=39/3=13
a-13=40=>a=40+13=>a=53
