To work this out, we must use the balancing method - whatever we do to one side, we do exactly the same to the other
-7 = e/3 + 14
(-14) (-14)
-7 - 14 = -21
-21 = e/3
(x3) (x3)
-21 x 3 = -63
-63 = e
e = -63
Sn=A1(1-r^n)/(1-r)
Sum of a finite geometric series formula
We know the sum, number of terms and rate, so you plug those in.
-255=A1(1-(-4)^4))/(1-(-4)
-255=A1(1-256)/5
-255=A1(-255)/5
-1275=A1(-255)
5=A1
Hope this helped! Let me know if you have any questions.
The pattern is 4, 12, 36, 108, 324, 972, 2,916
4+8=12
12+24= 36
36+72= 108
108+216=324 .... and so on
1. 6x-15
2. 18x-55
3. 7.2x+2.3y-2
$1000 - ($20 + $20) = $60
$60 / $10 = 6 paper weights
