Question

What is the equation of the line that passes through (1, 2) and is parallel to the line whose equation is 2x + y - 1 = 0?

Answer 1

Have you found the answer

Answer 2

y= -2x +4

Explanation:

The equation of a line is usually written in the form of y=mx+c, where m is the gradient and c is the y-intercept.

Parallel lines have the same gradient.

Let's rewrite the equation of the given line in the form of y=mx+c, so that we can obtain it's gradient.

2x +y -1= 0

y= -2x +1

Thus gradient of the line is -2.

subst. m= -2 into the equation:

y= -2x +c

To find the value of c, substitute a coordinate.

When x=1, y=2,

2= -2(1) +c

2= -2 +c

c= 2 +2

c= 4

Thus, the equation of the line is y= -2x +4.