Question

Select the arithmatic sequence from the following:

Select one:
a.-2, 3, 5, 10, 18
b.- 2.0, 8, 13, 17
C. - 2, 3, 8, 15, 20
d. - 2, 3, 8, 13, 18

Answer 1

`\huge\boxed{d.\ where\ a_1=-2;\ d=5}`

Explanation:

`\text{If}\ a_1,\ a_2,\ a_3,\ ...,\ a_n\ \text{is an arithmetic sequesnce, then}\\\\a_2-a_1=a_3-a_2=a_4-a_1=...=a_(n)-a_(n-1)=d=constant\\\\d-\text{common difference}\\\\\text{We have:}\\\\a.\ -2;\ 3;\ 5;\ 10;\ 18\\18-10\\eq10-5\\\\b.\ -2,\ 0;\ 8;\ 13;\ 17\\17-13\\eq13-8\\\\c.\ -2;\ 3;\ 8;\ 15;\ 20\\20-15\\eq15-8\\\\d.\ -2;\ 3;\ 8;\ 13;\ 18\\18-13=13-8=8-3=3-(-2)=5`

Answer 2

d) -2, 3, 8, 13, 18

Explanation:

d) is the only one that has the same change each time (+5)