Question

Tìm x, y

\(3x=7y;x-y=-16\)

Answer 1

Ta có: 3x=7y => x/7=y/3=(x-y)/(7-3) = -16/4=-4

=> x=-4*7=-28

     y=-4*3=-12

Answer 2

3x = 7y \(\Rightarrow\)  \(\frac{3x}{21}\)  = \(\frac{7y}{21}\)   \(\Rightarrow\)  \(\frac{x}{7}\)  = \(\frac{y}{3}\)   =   \(\frac{x-y}{7-3}\) = \(\frac{-16}{4}\)  = -4

Suy ra x = -4 . 7 = -28

             y= -4.3 = -12