Don't be shy about using actual parentheses and commas.
Line through (1,8) perpendicular to
The perpendicular family is gotten by swapping the coefficients on x and y, negating exactly one of them. The constant is given directly by the point we're through:
Let's clear the fractions by multiplying both sides by 20.
Might as well stop here.
Answer: 25 x + 16 y = 153