Frank has $8 000 that he plans to split into two investments. He wrote the following two equations to represent the interest he will earn from each of the two investment options.
2000A + 6000B = 520
4000A + 4000B = 480
Determine the interest rates, A and B, as percentages.​

x =±sqrt(1/3)

step-by-step explanation:

x+4/6x=1/x

multiply each side by 6x to get rid of the fractions

6x*(x+4/6x)=1/x*6x

distribute

6x^2 +4 = 6

subtract 4 from each side

6x^2 +4-4 = 6-4

6x^2 =2

divide by 6

6x^2/6 = 2/6

x^2 = 1/3

take the square root of each side

sqrt(x^2) = ±sqrt(1/3)

x =±sqrt(1/3)