Resposta :
x + y - 4 =0
x=4-y
2x - y + 1 = 0,
2(4-y)-y+1=0
8-2y-y+1=0
3y=9
y=9/3=3
x=4-y
x=4-3
x=1
´P(1,3)
As retas r e s, de equações x + y - 4 = 0 e 2x - y + 1 = 0, respectivamente, se interceptam num ponto P(a,b). Determinar as coordenadas do ponto P.
x + y - 4 =0
x=4-y
2x - y + 1 = 0,
2(4-y)-y+1=0
8-2y-y+1=0
3y=9
y=9/3=3
x=4-y
x=4-3
x=1
´P(1,3)