Algebra 1 Homework Help!!!?

Question

Heres the problem:
Ms. Sidher invests a total $18,000 into two accounts bearing simple interest; one account bears 5% and the other bears 8%. If she earns $1,260 interst for the year, how much did she invest in the account thats earns 8%?

I have to use the "tic tac toe" method if you know what that is.

Please show me how you did it to please!

I figured out the tic tac toe thing!

Answer 1

Let x be the amount in the 8% account:
Let 18000 - x be the amount in the 5% account.

0.05(18000 - x) + 0.08x = 1260
900 - 0.05x + 0.08x = 1260
0.03x = 360
x = 360 / 0.03
x = 12000

So you have 12,000 in the 8% account and 6,000 in the 5% account.

I'm not familiar with the tic tac toe method except when factoring polynomials.

Answer 2

If you let x be the amount of money you put in the account with 8% interest, the following equation can be formulated.

(18000 - x)(0.05) + x(0.08) = 1260
18000(0.05) - 0.05x + 0.08x = 1260
0.03x = 360
x = 12000

Therefore, she invested $12,000 into the bank account with 8% interest rate per annum.

Answer 3

let x = amount invested at 5%
let y = amount invested at 8%

x+y=18000
.05x+.08y=1260

x=18000-y
.05(18000-y)+.08y=1260

.03y+900=1260
.03y=360
y=360/.03=12000

So $12,000 was invested at 8%

Answer 4

1260 / 0.08 = 15,750