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Polynomials 04: Subtracting

Polynomials 04: Subtracting

Subtracting polynomials is pretty much the same as adding them in the last lesson except that we need pay close attention to the positive and negative values.

Keep in mind the rules
[math]+&- =-[/math]
[math]-&- =+[/math]

For instance if we needed to subtract [math]4x^2-3+7x[/math] from [math]5x-x^2+7+2x^3[/math] it would look like this [math] (5x-x^2+7+2x^3)-(4x^2-3+7x) [/math].

The first polynomial can stay the same but the signs in front of each term in the second must be reversed because it is combined with the subtraction term. [math]5x-x^2+7+2x^3-4x^2+3-7x[/math]. Like terms can then be combined to simplify. [math]2x^3-5x^2-2x+10[/math]

Remember to always watch the [math]+ & - [/math] signs carefully as that is what most often causes troubles

Directions for this Lesson:
Watch the video below and complete the practice questions as well as the worksheet.

Required Video: