Final answer:
The value of x for which a || b is 5.
Step-by-step explanation:
To determine the value of x for which a || b, we need to equate the given angles. Angle 1 = 60 - 2x and Angle 5 = 70 - 4x. Since a || b, corresponding angles are congruent, so Angle 1 = Angle 5. Setting the two expressions equal to each other:
60 - 2x = 70 - 4x
Subtracting 2x from both sides:
60 = 70 - 2x
Subtracting 70 from both sides:
-10 = -2x
Dividing both sides by -2:
x = 5