1. Dylan invested $47,000 in an account paying an interest rate of 4% compounded annually. Assuming no deposits or withdrawals are made, how long would it take, to the nearest tenth of a year, for the value of the account to reach $79,200? 2. x^2 + y^2 = 153 and y = -4x. If (x, y) is a solution to the system of equations above, what is the value of y^3?

(1) 13.0 years

(2) {-1728, 1728}

Step-by-step explanation:

(1)

Compound annually:

= A

(47000) = 79200

=

ln() = ln()

ln and e cancel out.

(0.04)(t) = ln()

t =

t = 13.0 years

(2)

Substitute y with -4x.

Solve for x.

x = {-3, 3}

Plug in x values into any equation to find y.

y = -4(-3) and y = -4(3)

y = {-12, 12}

= = -1728

= = 1728

3xy cannot be combined with the others

2x, -5x and x are like terms