Question

Resolva o sistema 2X+5Y=8 X-2Y=7

Answer 1

2x+5y = 8
x-2y =7 ---> x = 7 +2y
2.(7+2y) +5y = 8
14+4y+5y = 8
9y= 8-14
y=-6/9
y= -2/3

x-2y = 7
x- 2. (-2/3) = 7
x + 4/3 = 7
x = 7 - 4/3
x= (7-4)/3
x= 3/3
x=1