Question

Sa se afle media artimetica a numerelor a si b ,daca intre multimile {a;12;b} si {2a+4;40;20} se stabileste o proportionalitate directa.
Va rog mult sa ma ajutati .sunt in panica de timp si am nevoie de ajutorul vostru

Answer 1

a/(2a+4)=12/40=b/20

=>
a/(2a+4)=12/40
40a=12 (2a+4)
40a=24a+24
40a-24a=24
16a=24
a=24/16
a=3/2

12/40=b/20
12*20=40b
240=40b
b=240/40
b=6

media aritmetica=(3/2+6)/2=(3/2+12/2)/2=15/2*1/2=15/4