Find the equation of the line passing through 2 1 and parallel to the line 2x ndash y 4 ........

Explanation:

The given line is 2x – y = 4
⇒ y = 2x – 4 (Converting into the form of y = mx + c)
Its slope = 2. The slope of the parallel line should also be 2.
Hence for the required line
m = 2 and (x1 , y1) = (2, -1).
Equation = y - y₁ /x - x₁ = y₂ - y₁ /x₂ - x₁
⇒ y - y₁ /x - x₁ = m
⇒ y – y1 = m (x – x1) ⇒ y – ( - 1) = 2 (x – 2)
⇒ y = 2x – 5.