False planes do not have edges.
Answer:
I guess 21 is your answers.
Answer:
a = 7
Step-by-step explanation:
3(1 - 2a) = -3a - 18
3 - 6a = - 3a - 18
Add 18 to each side:
3 + 18 - 6a = - 3a - 18 + 18
21 - 6a = - 3a
Add 6a to each side:
21 - 6a + 6a = - 3a + 6a
21 = 3a
3a = 21
Divide each side by 3:
3a ÷ 3 = 21 ÷ 3
a = 7
(9 × 10) + (20x + 21) = 571
90 + 20x + 21 = 571
111 + 20x = 571
- 111
20x = 460
÷ 20
x = 23
I hope this helps!
