x+3=15
Subtract 3 from both sides
x+3-3=15-3
x=12
I hope that's help !
Check my answer
Replace x by 12
12+3=15
15=15
So... Yes my answer is correct !
Answer:
48
Step-by-step explanation:
given
n=9
a=1
d=3-1=2
now , by formula,
sn = n/2(2a+(n-1)d)
= 9/2(2×1+(9-1)×2)
=9/2×18
=81