Susan invests 3 times as much money at 13% as she does at 9%. If her total interest after 1 year is $1920, how much does she have invested at each rate? Susan invests $ at 9% and $ at 13%.

assume susan spend x dollars at 5%, so she has 3*x dollars at 9%

the total interest after a year is: 0.05*x + 0.09*3*x = 1280 => 0.32 *x = 1280 => x=4000

so 3*x = 12000

12000 at 9%, 4000 at 5%

Step-by-step explanation:

hello :

70y^8 + 30y^6 = 2 ( 35 y^8 + 15y^6)

the lenght is : 35 y^8

the width is : 15y^6