Splitting investments. Joan had $3,000 to invest. She invested part of it in an investment paying 8% and the remainder in an investment paying 10%. If the total income on three investments was $290, than how much did she invest at each rate?

Step-by-step explanation:

From the given information:

Let assume that the invested amount in the investment paying 8% interest is a

Now, since the total amount invested = $3000.

Then, the amount invested in the investment that will be paying 10% interest can be represented as:

= $(3000-a)

Income earned on $a that is being invested in 8% interest = $a × 8/100 = $0.08a

Income earned from $(3000-a)  in the 10% investment is:

= $(3000-a)× 10/100

= $(300 - 0.1a)

Since total income of the two investment = $290;

Then;

0.08a + (300 - 0.1a) = 290

0.08a + 300 - 0.1a = 20-

300 - 0.02a = 290

-0.02a = -10

a = -10/-0.02

x = 500

Thus;

the amount invested in an investment paying 8% interest = $500

the amount invested in an investment paying 10% interest = $(3000 - 500) = $2500

-13

step-by-step explanation:

f(x)=2x-5 for f(-4)

f(-4)   means let x=-4

f(-4) = 2(-4) -5

f(-4) =-8-5

      = -13

answer: the answer is 127 degrees