I'm solving tax problems using systems of linear equations. Help!

Question

Last year, Dan had 10000 to invest. He invested some of it in an account that paid 7% simple interest per year, and he invested the rest in an account that paid 6% simple interest per year. After one year, he received a total of $610 in interest. How much did he invest in each account?

Answer 1

X+y = 10000

0.07x + 0.06y = 610

0.07x + 0.06 ( 10000 - x) = 610

0.07x + 600 - 0.06x = 610

0.01x + 600 = 610

0.01x = 10

x = 1000

y =9000