Asap will mark ! what is the third number in the sequence? 1, 3, 13, 21, . . a. 5 b. 6 c. 7 d. 4

The third number in the sequence would be 7.

The sequence is gaining 2 from the first to second, 4 from the second to third, 6 from third to fourth and 8 from fourth to fifth.

1 + 2 = 3

3 + 4 = 7

7 + 6 = 13

13 + 8 = 21

21 + 10 = 31

31 + 12 = 43

This is the pattern in which the sequence follows and the answer is C. 7

225x²+4=0

225x²=0-4

225x²=-4

x²=-4/225

x=±√-4/225

168

step-by-step explanation:

i am pretty sure that the answer is 168