Răspuns :
7x+4y=7*2/3+4*9/5=14/3+36/5
amplificam prima fractie cu 5 iar a doua cu 3
=70/15+108/15=178/15
amplificam prima fractie cu 5 iar a doua cu 3
=70/15+108/15=178/15
7*2/5+4*9/5=14/3+36/5=(aducem la acelasi numitor 15)
deci 14*5/15+36*3/15=70/15+108/15=178/15
deci 14*5/15+36*3/15=70/15+108/15=178/15