Chapter 5, Systems of Equations and Inequalities - Section 5.1 - Systems of Linear Equations in Two Variations - 5.1 Exercises - Page 448: 71

$14000$ into the first one ($5\%$), and $6000$ into the second one ($8\%$).

If she invests $x$ in the first one, she invests $20000-x$ into the second one. Then our equation is: $0.05x+(20000-x)0.08=1180\\0.05x+1600-0.08x=1180\\0.03x=420\\x=14000$ Thus, she invested $14000$ into the first one ($5\%$), and $2000-14000=6000$ into the second one ($8\%$).