Solve the following system of equations with the substitution method:

`{(x, =, -5 y + 7),(4 x + 20 y,=,28):}`

Answer: ( , )

Enter your answers as integers or as reduced fractions in the form A/B. If there is no solution, type "DNE" in each blank. If there are an infinite number of solutions, specify their form in the blanks in terms of y.