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Write an equation of the line (2,-1) and parallel to the line y=-3x+8

An equation of the parallel line is y= ?

User Jdhao
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1 Answer

9 votes

Answer:


y=-3x+5

Explanation:

A line being parallel to another means it has the same slope, so the slope of the new line is also -3.

Slope-intercept form is:


y=mx+b

where m is the slope, b is the y-intercept, and (x, y) is any point on the line. There are 4 variables in this equation, and we're already given 3 of them (slope, x, and y), so we can solve for the 1 unknown variable (y-intercept).

Plug in all known values:


\rightarrow y=mx+b\\\rightarrow(-1)=(-3)(2)+b

Now, you can solve for b.


\rightarrow-1=(-3*2)+b\\\rightarrow-1=-6+b\\\rightarrow5=b\\\rightarrow b = 5

Finally, with both the slope and y-intercept, you can write the equation of the line:


y=-3x+5

Write an equation of the line (2,-1) and parallel to the line y=-3x+8 An equation-example-1
User Georg Pfolz
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