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Find the equation of the line that passes thru (-1,-5) and is parallel to 3x+y=-5. Show work.

Sagot :

Answer:

[tex]y=-3x-8[/tex]

Step-by-step explanation:

slope-intercept form:

[tex]y=mx+b[/tex]

Start with the given equation, and to find the slope, convert it to slope-intercept form by solving for y.

[tex]3x+y=-5[/tex]

In this case, all you need to do is subtract 3x from both sides.

[tex]y=-3x-5[/tex]

Here, the slope is -3. The slope of a parallel line will also be -3.

Now, we have 3 known variables. We have the slope and the x and y of a known point. Use those 3 knowns to solve for the 1 unknown, the y-intercept.

[tex]y=mx+b\\-5=(-3)(-1)+b\\-5=3+b\\-8=b\\b=-8[/tex]

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

[tex]y=-3x-8[/tex]