Finished except for the last two here: please include explanations (not just solutions)

#8.B) _solve each system of equations. state which systems _if any_ have no solution or infinite number of solutions

c)

x - y - 2z = 3

x + 2y + z = 1

3y + 3z = -2

d)

2x - 2y + 3z = 4

x - 3y + 2z = 2

x + y + z = 1

#9 __the sum of 3 integers is 189. the first integer is 28 less than the second. the second integer is 21 less than the sum of the 1st and 3rd integers. find the 3 integers__