x15x22x3 - 10x4 = -43 - 2x19x2 x3 - 3x4 = 5 -8x1 + x2 - 2x3 + 3x4 = 0 - 2x1 x27x3 - 2x4 = 13 Find x1, x2, x3, and x4 using the following methods: a. Solve by hand calculation using Cramer's rule. (15 pts) b. Solve by hand calculation using the Gauss-Seidel method. Do it for three iterations (10 pts) c. Verify your answer by writing a C program to solve the above using the Gauss- Seidel method (10 pts) Try three and four iterations and show the assembler output.