I would like some help with this! Will mark brainliest :)

a(n) = 10n-1 (the second one)

Step-by-step explanation:

we use formula

a(n) = a +(n-1)d    (a= the first number in the, n=the times we need, d= difference)

a=9

d=9-19=10

a(n) = 9 +(n-1)10

a(n) = 9 +10n-10

a(n) = 10n-1 (the second one)

I hope it will help

1/2

Step-by-step explanation:

3/4 × 2/3

3 × 2/4 × 3

6/12 = 1/2

Thus, 3/4 × 2/3 = 1/2

-TheUnknownScientist