When you have parallel lines cut by a transversal, alternate interior angles are congruent.
The 80 degree angle and the (20 + x) angles will be congruent.
Therefore, x = 60 degrees.
Answer:
n < 20
Step-by-step explanation:
2n – 1 < 39
Add 1 to each side
2n – 1+1 < 39+1
2n < 40
Divide each side by 2
2n/2 < 40/2
n < 20
Answer:
Let 2x + y - 10 = 0 be equation (a).
Let x - y - 5 = 0 be equation (b).
Make y the subject in equation (b):

Substitute for y in equation (a):

Find y in any equation of your choice:

1st element can be matched with 5
2nd element can be matched with 4
3rd element can be matched with 3
etc.
Total number of correspondences = 5*4*3*2*1 = 120