Question

LOOK AT ATTACHMENT
PLEASE HELP
MEDAL + FAN

Answer 1

D

Answer 2

how do you figure @yahman

Answer 3

TRUST MEE

Answer 4

the general formula of arithmetic sequence is :
an = a1 + (n-1)d

so,
a7 = 19
=> a1 + 6d = 19

a12 = 54
=> a1 + 11d = 54

by using elimination method, subtract both equation above :
a1 + 11d = 54
a1 + 6d = 19
-------------- (-)
5d = 35
d = 35/5 = 7

subtitute d = 7 into the 2nd equ :
a1 + 6d = 19
a1 + 6(7) = 19
a1+ 42 = 19
a1= 19 - 42
a1 = - 23

now, to get the value of a15 just distibute into general formula :
an = a1 + (n-1)d
therefore,
a15 = -23 + (15-1)7
a15 = -23 + 14 * 7
a15 = -23 + 98
a15 = 75

Answer 5

does that make sense ?

Answer 6

sort of @RadEn

Answer 7

C