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The equations of four lines are given. Identify which lines are parallel.

Line 1:
y=-7x + 6
Line 2:
x +1/5y=-6
Line 3:
y=-5x -8
Line 4:
y+7=-1/7(x+4)

User Pleft
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1 Answer

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Answer:

Line 2 and 3 are parallel

Explanation:

Recall that the general equation of a line in slope-intercept form is given by:

y = mx + b

where m is the gradient (slope).

two different equations that have the same value of m is said to have the same gradient and hence are parallel.

We simply have to rearrange each given equation so that it takes the form

y = mx + b and then compare all 4 to see which values of m are the same.

Line 1 : y = -7x + 6

Line 2: x +(1/5)y=-6 ===> rearrange to get y = -5x - 30

Line 3: y= -5x -8

Line 4: y+7=(-1/7)(x+4) ===> rearrange to get y = (-1/7)x - (53/7)

comparing the above, it is clear that line 2 and line 3 have m- values of m = -5, hence these lines are parallel.

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