Question

In the given figure, l || m. Find the value of x so that the lines AB and CD are parallel.
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Answer 1

Answer:

x = -5

Step-by-step explanation:

4x-10=3x-15 (alternative)

4x-3x = -15 +10

x = -5

(you can also see by putting value)

Answer 2

Answer:

4x -10 = 3x+15 ( exterior alternate angle)

4x-3x = 15 + 10

x = 25

Now as

4x -10 = 90 degree

and 3x + 15 = 90 degree

Hence, AB and CD are parallel.