First we need to find the slope of the given line, so we could find the slope of the line perpendicular to that. Since 3x - 6y = 9, we could subtract 3x from both sides, giving -6y = -3x + 9. Now divide everything by -6y to get y=(1/2)x-(3/2). Since this is the form y=mx+b, the slope is 1/2. So the line perpendicular has a slope -2. Since it passes through (-2, -1), we can write the equation in point-slope form as y+1=-2(x+2). But we need this in standard form, Ax+By+C=0:
y + 1 = -2x - 4
2x + y + 5 = 0
These coefficients are all integers, so we are done:
