help please

Question

Perform the indicated operations:

 

A) (2x^3-3x^2+x-1)-(x^3-3x+4)

 

B) (x^2-2x-1)(x+3)

Answer 1

For part B, you can also think of one of the factors as the GCF.  Then rewrite the expression in distributive property form.  This method will help you to keep track of how you handle the terms between polynomials.

 

Use (x² - 2x - 1) as the GCF. 

 

 

x(x² - 2x - 1) + 3(x² - 2x - 1) =

 

x³ - 2x² - x + 3x² - 6x - 3

 

 

Combine like terms to simplify.

 

x³ + x² - 7x - 3

Answer 2

A) First you need to distribute the subtraction sign to the second set of parenthesis. 

 

2x^3-3x^2+x-1-x^3+3x-4

 

Then add like terms. 

 

X^3 - 3x^2 + 4x -5

 

B) For this one, you're going to multiply all factors in the second set of parentheses to the first and then add like terms. Remember, when multiplying variables with exponents, you add the exponents together. 

 

X^3-2x^2-x+3x^2-6x-3

 

x^3+x^2-7x-3