Linear Algebra help

Find all solutions to the following systems of linear equations.

(a) x1 − 2x2 + 2x3 = 5

x1 − x2 = −1

−x1 + x2 + x3 = 5

(b) x1 + x2 + 3x3 = 3

−x1 + x2 + x3 = −1

2x1 + 3x2 + 8x3 = 4