In 5 years, Gloria’s bank account earned $2,400 interest at 5%. How much had she deposited in the account?

$1880.5 to the nearest tenth.

Step-by-step explanation:

I am assuming that the interest is compounded each year.

If P is the original amount deposited:

2400 = P(1 + 0.05)^5

1.05^5 P = 2400

P = 2400 / (1.05)^5

P = $1880.5 to the nearest tenth.

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so:

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!