book Maths Puzzle Numerical Ability

please help me with this problem i have no idea how to get the answer and i have been working on it for an hour. solve the system of equations.
3x+4y+z=7
2y+z=3
-5x+3y+8z=-31
thank you!!!

Read Solution (Total 0)

book Other Question
Im starting out with fourteen now i subtract 4 the Multiply by 7 then i have to make up how much at divide and add The integers from 1 to 1000 are printed on a list how many time does the digit 3 appear?