I need help with systems of equations using THREE variables. The process is complicated for me given that I am not the best at Matrices. Please help explain.

Solve 2x + 3y + 3z = 5

4x + 5y + 3z = 13

3x + 2y - 2z = 13

Solve x + 2y + z = 5

2x - y + z = 4

3x + y + 4z = 1

Solve x + 2y + z = 5

2x - y + z = 4

3x + y + 4z = 1

Twice the first number is eleven more than the sum of the other two numbers. The sum of twice the first number and three times the third number is one more than the second number. The second number is equal to the sum of the first number and the third number. Find the three numbers.

The sum of the length, width, and height of a rectangular box is 16 cm, the width is twice the height, and twice the length exceeds the sum of the width and height by 5. Find the length, width, and height of the box.