Well if finding X you get 4,-7 when you simplify the whole equation you get that as well.
Answer:
given
n=9
a=1
d=3-1=2
Step-by-step explanation:
now , by formula,
sn = n/2(2a+(n-1)d)
= 9/2(2×1+(9-1)×2)
=9/2×18
=81
Answer:
Answer:
3x + 3y = 0
7x - y = 8
Step-by-step explanation: