The following sets of linear equations have common coefficients but different terms on the left side:

a$).-$

$x+y+z=,1$

$2x-y+3z=,4$

$3x+2y-2z=,-2$

b$).-$

$x+y+z=-2$

$2x-y+3z=5$

$3x+2y-2z=1$

c$).-$

$x+y+z=,1$

$2x-y+3z=,4$

$3x+2y-2z=,-2$

The three equations above can be combined in the following arrangement:

$1111-22$

$2-1345-1$

$32-2-214$

Make a program of forward elimination and backward

substitution in a Fortran f$.90$ code to be able to solve the problem of the three equations at the same time.