ALGEBRA professor leads I need assitance with 3 problems

1. Use the Substitution methodto solve this system of linear equations: 4x − y = 5

−x + y = −2

2. Solve this nonlinear system of equations using Substitution. 3x² + 4x – y = 7

2x – y = –1

3. Form the augmented matrix and then use the Gauss-Jordan Elimination method to solve this linear system:

x + y + 2z = 1

−x + z = −2

2x + y + 5z = −1