Video Transcript
Line 𝐿 passes through points
negative one, two and two, three, and line 𝑀 passes through points negative one,
negative one and five, one. Work out the slope of line 𝐿. Work out the slope of line 𝑀. Are these two lines parallel?
We have two lines, line 𝐿 and line
𝑀. The first thing we’re asked for is
the slope of both of these lines. The slope is the changes in 𝑦 over
the changes in 𝑥. If we have two points, we can find
the slope by subtracting 𝑦 two minus 𝑦 one and putting that over 𝑥 two minus 𝑥
one.
For line 𝐿, we have our two
points. We can label the first point 𝑥
one, 𝑦 one and the second point 𝑥 two, 𝑦 two. 𝑦 two minus 𝑦 one equals three
minus two. And 𝑥 two minus 𝑥 one is two
minus negative one. Three minus two is one. Two minus
negative one equals three. The slope of line 𝐿 is
one-third.
We’ll follow the same process for
line 𝑀. We take the two points. We’ll call the first point 𝑥 one,
𝑦 one and the second 𝑥 two, 𝑦 two. 𝑦 two minus 𝑦 one is one minus
negative one over 𝑥 two minus 𝑥 one, five minus negative one. One minus negative one is two. Five minus negative one is six.
We can reduce the fraction
two-sixths. If we divide the numerator and the
denominator by two, two-sixths is reduced to one-third. The slope of line 𝑀 is also
one-third.
The last question is, are the two
lines parallel? We remember that parallel lines
have the same slope. Since line 𝐿 and line 𝑀 have the
same slope, they are parallel lines.
