{х+у=7 {-х+2у=-4 плиииз

Question

{х+у=7
{-х+2у=-4 плиииз

Answer 1

X = 7 - Y 
- ( 7 - Y) + 2Y = - 4 
- 7 + Y + 2Y = - 4 
3Y = - 4 + 7 
3Y = 3
Y = 1 
X = 7 - 1 = 6