Respostas

2014-03-12T22:33:44-03:00
2x+y=6,50

x+2y=7
x=7-2y

2(7-2y)+y=6,50
14-4y+y=6,50
14-3y=6,50
-3y=6,50-14
-3y=-7,50
y=2,5

x+2.2,5=7
x+5=7
x=7-5
x=2

cada empada custa 2,5 reais e coxinha 2
1 5 1
2014-03-12T22:37:51-03:00
2c + 1e = 6,5. X(-1). //. -2c -1e = -6,5
1c + 2e = 7,0. X(2). //. 2c + 4e =14,0

-> 3e = 7,5. // substituindo...
E = 7,5/3 // ->> 2c + 1e = 6,5
E = 2,50 // 2c + 2,5 = 6,5
// 2c = 6,5 - 2,5
//. 2c = 4,0
// c = 4,0/2 = 2,0

Logo, Empada = 2,50
Coxinha = 2,00
1 5 1