The following augmented matrix is in​ row-echelon form and represents a linear system. Solve the system by using​ back-substitution, if possible.

Question

[1 2| 5]

[0 1| -1]

Answer 1

(1)x + 2y = 5 and 0x + (1)y = -1

So, y = -1 and x = 7.