Struggling in Algebra, PLEASE HELP ASAP!!

Question

A mother wants to invest

​$13000

for her​ children's education. She invests a portion of the money in a bank certificate of deposit​ (CD account) which earns​ 4% and the remainder in a savings bond that earns​ 7%. If the total interest earned after one year is

$ 780,

how much money was invested at each​ rate, CD Account = ?

Savings Bonds= ?

Round to nearest cent

Answer 1

Let x = amt invested in the CD, then 13000-x = amt invested in bonds

780 = .04(x) + .07(13000 - x)

780 = 910 - .03 x

x = 4333.33