**Q: Add: (3x ^{3}+2x^{2}-5x) + (-4x^{3}-x^{2}-8x)**

A: Here we are just asked to clean things up and combine like terms: basically, add apples with apples and oranges with oranges, but don’t accidentally add apples with oranges!

x^{3} terms get added with x^{3} terms

x^{2} terms get added with x^{2} terms

x terms get added with other x terms

So, let’s use color to highlight the like terms:

**(3x ^{3}+2x^{2}-5x) + (-4x^{3}–x^{2}-8x)**

How many total **x ^{3}** terms do you have?

**3x**= -1

^{3}+ -4x^{3}**x**

^{3}How many total **x ^{2}** terms do you have?

**2x**+

^{2}**–x**= 1

^{2 }**x**

^{2}How many total **x** terms do you have? **-5x**+ **-8x = -13x**

Did we forget anyone? Did anyone not have a match that we need to bring along? Nope! Everyone from both sets of parentheses is accounted for!

So, final answer:

**(3x ^{3}+2x^{2}-5x) + (-4x^{3}–x^{2}-8x)** = -1

**x**+ 1

^{3 }**x**–

^{2 }**13x**

Since we tend not to write the “1”, you might see the answer displayed as:

–**x ^{3 }**+

**x**–

^{2 }**13x**