You invested $18,000 in two accounts paying 7% and 8% annual interest, respectively. If the total interest earned for the year was $1290 how much was invested at each rate?

$15,000 was invested at 7%

$3,000 was invested at 8%

Step-by-step explanation:

Let be the amount of money you spend on the 7% account and be the amount of money you spend on the 8% account. With the information given, you can set up two equations:

Rearrange the first equation and multiply the second equation to get:

Then, substitute for in the second equation to get:

Use the distributive property () to get:

Subtract from both sides and combine like terms to get:

Thus, substitute for in the first original equation to get:

Finally, subtract from both sides to reach:

Our answer is $15,000 was invested at 7% and $3,000 was invested at 8%.

Hope this helps :)

since we know that the two functions are equal, f (x) = g

(x), therefore when we equate the two equations the result should be similar to

3x = x – 4:

a. f(x) = 3x, g(x) = x – 4

equating the two functions:

3x = x – 4             (correct)

so we now got our answer (a)