The first two rows of coefficients are identical, so by inspection, the determinant is 0.
96÷2=48
63-48=15
So Sam should give Peter 15 of his stamps so that Peter will have twice as many stamps as him.
So we are given a system:

Substitute x = 2 we get the system:

Multiply the first equation by -5 and the second by 2 we get the system:

Adding the two equations we get :

We find the value of y by using any of the other equations like this:

Final solution:
I believe Z=18
Example:
2/3z + 1 = 13
Multiply both sides: 2/3z * 3 + 1 * 3 = 13 * 3
Refine: 2/3z + 3 = 39
Subtract from both sides: 2z + 3 - 3 = 39 - 3
Refine: 2z=36
2z/2 = 36/12
Z=18
Answer:
this is the answer 25
Step-by-step explanation:
i guessed