3, a*b=30*0,1
a*b=3
4. x-20x/100=14
(10x-2x)/10=148
8x=1480
x=1480/8
x=185 pretul initial
5 . 7a=6b rezulta a=6b/7
A) b-a=b-6b/7
=(7b-6b)/7
=b/7
b+a=b+6b/7
=(7b+6b)/7
=13b/7
(b-a)/(b+a)= b/7 * 7/13b se simplifica 7 cu 7 si b cu b si ramane =1/13
B) 3a-2b= 18b/7 - 2b
=(18b-14b)/7
=4b/7
a+b=b+a=13b/7
(3a-2b)/(a+b)=4b/7 * 7/13b se simplifica 7 cu 7 si b cu b si ramane
= 4/13
2. 1ha=10000m^2
55ha=550000m^2
calculam aria unei gradini=110*50=5500m^2
impartim aria parcului la aria unei gradini pentru a afla cate gradini se pot amenaja= 550000/5500= 100 gradini
