Question

x supra 4 minus x ori 1 supra 9 egal 4

Answer 1

x/4-x·1/9=4 ⇔ x·1/4-x·1/9=4 ⇔ x·(1/4-1/9)=4  Se aduc fractiile la acelasi numitor prin amplificarea uneia cu numitorul celeilalte)
x·(9/36-4/36)=4 ⇔x·5/36=4 ⇔ x=4:5/36 ⇔ x=4x36/5 ⇔ x=144/5