Find the Flaw in the Proof Given x y z 5x 5y 5z 4z 4x

Find the Flaw in the Proof

Given: x + y = z

5x + 5y = 5z

4z = 4x + 4y

Adding:

5x + 5y + 4z = 4x + 4y + 5z

Subtracting 9z from both sides:

5x + 4y – 5z = 4x + 4y – 4z

Grouping terms:

5(x + y – z) = 4(x + y – z)

Dividing both sides by (x + y – z):

5 = 4

5x + 4y – 5z = 4x + 4y – 4z

Grouping terms:

5(x + y – z) = 4(x + y – z)

Flaw is in this step as middle term is 4y and 5 cannot be taken out as common.