Combining Like Terms

6x⁴ - 3x - 2x⁴ + 2x
= 4x⁴ - x
​Why does it not equal 4x⁴ - 5x ?

Trying to help my son who thinks the - before the 3x is a minus sign not a negative sign. So why do I simplify this part as -3x + 2x = -x, he thinks it should be 3x + 2x = 5x, which is subtracted from the 4x⁴.

---

Whether it is considered a negative sign or a minus sign all depends on how it is used in the given situation.

In this case, you are to combine the like terms....-3x and 2x.....just think “the sign in front of the term goes with it, when combining like terms”

6x⁴ - 3x - 2x⁴ + 2x
= 4x⁴ - x {combined 6x⁴ with -2x⁴ to make 4x⁴ , and combined -3x with 2x to make -x}

Interesting, that he didn’t think it was 6x⁴ + 2x⁴, probably because the 6x⁴ was the leading term when combining, and the -2x⁴ came after it.

The sign in front of the term goes with the term!

Ask the House

Leave a Tip