Question

verifique se os pontos A( 0,4), B ( 2,0 ) e C (4,2) pertencem ou nao a reta (s) x-2y-2=0

Answer 1

reta x-2y -2 = 0
-y = -1/2x+1
y=1/2x-1

x =0 y = -1
x = 1 y = -1/2
x= 2 y = 0
x= 3 y = 1/2
x=4 y = 1

Passa somente pelo ponto B

Answer 2

E ae manoo,

só substituir as coordenadas (x e y), na reta, se for igual a zero, pertence, senão, não pertence..

 Verificando os pontos A,B e C:

$\boxed{x-2y-2=0}\\\\\\ PONTO~A:\\x~~~~~~~y\\0-2\cdot4-2=0\\ 0-8-2=0\\ -10 \neq 0~~(nao~pertence)\\\\ PONTO~B:\\x~~~~~~~y\\2-2\cdot0-2=0\\ 2-0-2=0\\ 2-2=0\\ 0=0~~(pertence)$

$PONTO~C:\\x~~~~~~~y\\4-2\cdot2-2=0\\4-4-2=0\\ 0-2=0\\ -2 \neq 0~~(nao~pertence)$

Portanto só o ponto B pertence à reta x-2y-2=0.

Tenha ótimos estudos ;D