Let's convert the equation into slope-intercept form.
3x + 18y = 4 Subtract 3x from both sides. 18y= -3x + 4 Divide both sides by 18. y = -3/18x + 4/18 Simplify. y = -1/6x + 2/9
To make a line perpendicular, we need the slope to be the reciprocal of the other. Flip the denominator and numerator, and change the sign. We also have to change the b to make the line go through (-2, 1)
-1/6 to +6/1, or 6.
y = 6x + b
Input the x and y values and solve for b.
1 = 6(-2) + b 1 = -12 + b Add 12 to both sides. 13 = b
