Question

Barry simplified 5x – 3y – x + 6z, as shown.

5x – 3y – x + 6z

5x – x – 3y + 6z

5 + 3yz

Describe two mistakes Barry made, and find the correct solution.

Answer 1

Explanation:

Sample response: Barry incorrectly subtracted 5x – x because the coefficient of x is 1. The difference should be 4x. Barry incorrectly combined –3y and 6z because they are not like terms. The correct answer is 4x – 3y + 6z.

Answer 2

we have that
5x – 3y – x + 6z
5x – x – 3y + 6z------> this step is correct
5 + 3yz------> is not correct
because

1) 5x-x=5---> is not correct
the correct is
5x-x=4x

2) -3y+6z=3yz-----> is not correct
the correct is
-3y+6z=3*(2z-y)

therefore

the correct solution is
4x+3*(2z-y)