Find the equation of a line that is parallel to the line x equals negative 1x=−1 and contains the point left parenthesis negative 2 comma 1 right parenthesis .

The equation of the line is given as [tex]y-x=-1[/tex]

A straight line equation is given in the form [tex]y=mx+c[/tex] where [tex]m[/tex] is the gradient and [tex]c[/tex] is the y-interest.

We need to rearrange [tex]y-x=-1[/tex] to make [tex]y[/tex] the subject. 
[tex]y= x-1[/tex] ⇒ from here we can read the gradient and the y-intercept. The gradient, [tex]m=1[/tex] and [tex]c=-1[/tex].

A line that is parallel to [tex]y=x-1[/tex] will have the same gradient, [tex]m=1[/tex] but different y-intercept. One example of equation of a line that is parallel to [tex]y=x-1[/tex] is [tex]y=x+3[/tex]