(r^2+r-1)(r^2+6r-8)

Question

(r^2+r-1)(r^2+6r-8)

Answer 1

(r² +r -1)(r²+6r-8)

 

Distribute each term from polynomial to the terms in the second polynomial.  This is based on the FOIL method, but it is extensive.

 

 

As a result, we end up with a product of

 

 

r²(r² + 6r - 8) + r(r² + 6r - 8) + [-1(r² + 6r - 8)] =

 

r⁴+ 6r³ - 8r² + r³ +6r² - 8r - r² - 6r -8 =

 

r⁴ + 7r³ - 3r² - 14r - 8

 

 

 

Answer 2

(r^2+r-1)(r^2+6r-8) 

 

Multiply the first term in the first expression by each term in the second expression.

                                         r⁴ + 6r³ -8r²

Multiply the second term in the first expression by each term in the second expression.

                                                 r³ + 6r² - 8r  

Multiply the third term in the first expression by each term in the second expression.

                                                      -  r² - 6r + 8

Finally add like terms together.

                                          r⁴ + 7r³ - 3r² -14r +8  Answer: