A = 2 1..............b = 3

......4 3...................4

Given the matrix A and vector b and an unknown vector x

such that x = x1

...................x2

expand as a set of equations and solve them to find x

Ive been tryng to do this using 'Gaussian Elimination' using the upper triangular matrix form, i can figure out 'x2' as being '-2', but i just cant figure out how to get 'x1' which is '5/2'.

Ive asked for help in other places but they seem very eager to offer answers with no working out or methods whatsoever so its of no help to me. If i can figure this out, ill be able to answer the one that will up on my exam paper on Tuesday >.<

Thanks for reading