Answer:
x = 2
Explanation:
From the data, we obtain the slope :
-1, 8 ; 3, - 4
Slope = Rise / run
Rise = y2 - y1 = (-4 - 8) = - 12
Run = x2 - x1 = (3 - (-1)) = 4
Slope, m = - 12 / 4 = - 3
Recall:
Equation of line :
y - y1 = m(x - x1)
y - 8 = - 3(x + 1)
y - 8 = - 3x - 3
y = - 3x - 3 + 8
y = - 3x + 5
Substituting y = - 3x + 5 into the equation 2x+4y= 0
2x + 4(-3x + 5) = 0
2x - 12x + 20 = 0
-10x = - 20
x = 2