Question

3)verifique se a r :5x-y-8=0 passa pelos pontos :
A) (1,1)
B)(2,2)
C)(3,7)
D)(4,11)
E)(0,8)​

Answer 1

Resposta:

3)

5x - y - 8 = 0

y = 5x - 8

y = 5 - 8 = -3 não passa

y = 5*2 - 8 = 2 passa

y = 5*3 - 8 = 7 passa

y = 4*3 - 8 = 4 não passa

y = -8 não passa

4)

3x + 2y = 6

3x + 0 = 6

x = 2

A(2,0)

3*0 + 2y = 6

y = 3

B(0,3)

x + y = -16

y = -16

C(0, -16)

x = -16

D(-16,0)

Answer 2

$\boxed{\begin{array}{l}\sf r:5x-y-8=0\\\sf A(1,1)\\\sf 5\cdot1-1-8=5-9=-4\ne0\implies A(1,1)\not\in~r\\\sf B(2,2)\\\sf 5\cdot2-2-8=10-10=0\implies B\in~r\\\sf C(3,7)\\\sf 5\cdot3-7-8=15-15=0\implies C\in~r\\\sf D(4,11)\\\sf 5\cdot4-11-8=20-19=1\ne0\implies D\not\in~r\\\sf E(0,8)\\\sf 5\cdot0-8-8=0-16=-16\ne0\implies E\not\in~r\end{array}}$