Question

A line passes through (1,2) and is perpendicular to y=3.

(i) What is the equation of this line?
(also how do you get the answer)

Answer 1

As the line is perpendicular to y = 3 it well be of the form x = some number.
And the point (1,2) has an x-coordinate of 1 so the line passes through x = 1.

Equation of the required line is x = 1. Answer

Answer 2

make a graph and put a point at exactly (1,2) and then make a like at y=3 make a line through the point and you'll see that this is an undefined equation x cant equal all those numbers