Answer:
Use demos or a graphing calc.
Step-by-step explanation:
20,000 will be the population 40 years from now.
If it is a system of two unknowns:
1) 4x-8y=5 multiple by 3
2)6x-12y=10 multiple by -2
then
12x-24y=15
-12x+24y=-20
x and y equals 0, so
Answer: no solution