(x – y + 3z) from (2z – x – 3y)
The difference of two like terms is a like term whose coefficient is the difference of the numerical coefficient of the two like terms.
We have,
= (2z – x – 3y) – (x – y + 3z)
Change the sign of each term of the expression to be subtracted and then add.
= 2z – x – 3y – x + y – 3z
= (2z – 3z) + (– x – x) + (- 3y + y)
= (2 – 3)z + (– 1 – 1)x + (- 3 +1)y
= -1z – 2x – 2y
