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
y = 6x + 13