We have that
<span>n (n-1) -4
for n=1
a1=1*(1-1)-4------> a1=-4
for n=2
</span>a2=2*(2-1)-4------> a2=-2
for n=3
a3=3*(3-1)-4------> a3=2
for n=4
a4=4*(4-1)-4------> a4=8
the answer is
-4,-2, 2, 8
Interesting question. Does that mean near the end of humanity?
Solution 1:
10^10 = 1,000,000,000
10^12 = 100,000,000,000
100,000,000,000/1,000,000,000 = 100 trees per person
Solution 2:
10^12 / 10^10 --- 10^10 / 10^10
10^2/1 = 10^2 = 100 trees per person
Any of 9's multiples besides 9 and 18 will work.
So: 27, 35, 45, 54 ,63, 72, 81, 90, 99, 108, 117, 126, 135, and so on
Because the discriminant is less than zero, there are no real solutions in the equation.
