Answer:
-2
Step-by-step explanation:
Dividing the given equation by x, we find y to be ...
y = -2/x
Then ...
dy/dx = 2/x^2
and ...
dy/dt = (2/x^2)dx/dt
dx/dt = (x^2/2)dy/dt
When dy/dt = -4 and x=-1, this is ...
dx/dt = (-1)^2/2(-4) = (1/2)(-4)
dx/dt = -2
You will have $24 824.94 eight years from now.
The formula for the future value (FV) of her investment is
FV =<em>C</em>(1 + <em>r</em>)^<em>n</em>
where <em>C</em> = her initial cash
<em>r</em> = the interest rate
<em>n</em> = the number of years
FV = $15 000(1.065)^8 = $24 824.94
<span>As you have two fractions, you can cross multiply them. This gives: x/a = y/b to ay = xb. Then divide both sides by b to isolate x: ay/b = x.</span>