Răspuns :
4/5x+1/2x=7/10
(8+5)/10x=7/10
13/10x=7/10
10x*7=13*10
70x=130
x=130/70
x=13/7
(8+5)/10x=7/10
13/10x=7/10
10x*7=13*10
70x=130
x=130/70
x=13/7
(4/5x)+(1/2x)=7/10 <=> (8+5)/10x=7/10 <=> 13/10x=7/10 <=> (inmultim cu 10x ca sa scapam de numitor) 13=7x => x=13/7