Question

Aflati x din proportile. 5\x=10\7
Xpe 3 = 5pe9
4pe21=xpe7
25pe4=5pex
Cat mai repede va rog !!!

Answer 1

5/x=10/7=>5×7=10x=> 10x=35=>x=35/10=7/2

x/3=5/9=>x=(3×5)/9=>x=5/3

4/21=x/7=>x=(4×7)/21=>x=4/3

25/4=5/x=>x=(4×5)/25=>x=4/5

Answer 2

5/x=10/7=>x=5x7/10=35/10=3,5
x/3=5/9=>x=3x5/9=15/9=1,6666667
4/21=x/7=>x=4x7/21=28/21=1,(3)
25/4=5/x=>x=4x5/25=20/25=0,8