Is this relation a function{(1,2),(3,5),(6,7),(8,2)}?

Si el duplo del mayor de dos numeros se divide entre el el triplo del menor, el cocient es 1 y el residuo 3, y si 8 veces el menor se divide por el mayor, el cociente es 5 y el residuo 1

Use matrices to solve this linear system: 5x1 − 2x2 = −30 2x1 − x2 = −13 x1 = x2 =

Maria has $10,000 to invest in two accounts.he decides to invest one part in an account with 5% interest and the rest in an account with 8% interest. at the end of the year he has earned $702,50 in interest.¿how much did maria invest in the 8% account?