JAMB 1992 · UME · Q33

Find the equation of the line through $(5, 7)$ parallel to the line $7x + 5y = 12$ .

Worked solution (try it first)

Parallel lines have the same gradient, so the new line keeps the same left-hand side: $7x + 5y = k$ .
Put in the point $(5, 7)$ : $k = 7(5) + 5(7) = 35 + 35 = 70$ .
So the line is $7x + 5y = 70$ , option B.