Answer:
A: ≤ means less than OR equal to. < only means less than
B: 9
Explanation:
A: Because it would equal 19, and 19 is EQUAL than 19. 4(5) - 1 would equal 19, which is equal to 19, and not less than. ≤ means less than or equal to. < means less than. So its not true.
B: 47 - 2, 45. Then 5 x 9 equals 45. So 5 x 9 equals 45, then add 2 would equal 47.
Hope this helps <3
Electromagnetic waves can travel in vaccum but mechanical wave does not
Answer:
cooooooooooooooollllllllll
Explanation:
it would be a chain reaction and a wave