1. Consider the following system of equations:

X1 -3X2 - 8X3 = -15

X1 + 10X3 = 9

-X1 + 20X2 + X3 = 42

a) Solve the above system by Guassian Elimination method and justify your answers.

Carry out your calculations for four decimal digits and show your work. Check your

answers by using Matlab and compare.

2. Solve the system:

4X1 -X2 = -20

XJ-1 - 4XJ + XJ+1 = 40, 1

-Xn-1 + 4Xn = -25

a) Write the above system in matrix form.

Solve the system for n =4. Carry out your calculations for four decimal digits and show your work. Check your answers by using Matlab and compare.