9 because 18÷2=9
you can use models to help too
get 18 things and put them in 2 groups
Answer:
The amount in the account at 12% interest is $3400 and the amount in the second account at 7% interest is $2600
Step-by-step explanation:
Let x be the amount in the account at 12% interest
So, 6000-x is the amount in the second account at 7% interest

First account:
Second account : 
We are given that At the end of the first year he had earned $590 in interest.
So, 
So,the amount in the account at 12% interest is $3400
The amount in the second account at 7% interest =6000-x=6000-3400=2600
Hence the amount in the account at 12% interest is $3400 and the amount in the second account at 7% interest is $2600
the x and y values makes both equations true
Explanation
a linear system is the set of 2 linear equations.
Step 1
the solution to a linear system is the coordiante where the line intersect, this coordiante satisfies both equations, then
the x and y values makes both equations true
F(g(x)) = [(-7x-8)/(x-1) - 8} / [(-7x - 8)/(x-1) + 7] =
[(-7x - 8 - 8(x-1)) / (x-1)] / [(-7x - 8 + 7(x-1)) / (x-1)] = (-15x) / (-15) = x.
g(f(x)) = [-7*(x-8)/(x+7) - 8] / [(x-8)/(x+7) - 1] =
[(-7x + 56 -8*(x+7)) / (x+7)] / [(x - 8 - (x + 7)) / (x+7)] = (-15x) / (-15) = x.
So since f(g(x)) = g(f(x)) = x we can conclude that f and g are inverses.