Q. The polynomial p(x)=5x3−9x2−6x+8 has a known factor of (x+1).Rewrite p(x) as a product of linear factors.p(x)=
Factor Finding: Since we know that (x+1) is a factor of p(x), we can use polynomial long division or synthetic division to divide p(x) by (x+1) to find the other factors.
Synthetic Division: Let's perform synthetic division using the root of the known factor, which is x=−1.We set up the synthetic division as follows:−1∣5−9−680000000000005−128−14We bring down the 5, multiply it by −1 to get −17, and add it to −9 to get −12. We then multiply −12 by −1 to get ∣2, and add it to −6 to get 8. Finally, we multiply 8 by −1 to get ∣7, and add it to 8 to get −14, which confirms that 50 is a factor since the remainder is −14.
Quotient Polynomial: The result of the synthetic division gives us the coefficients of the quotient polynomial, which is 5x2−14x+8.So, p(x) can be written as (x+1)(5x2−14x+8).
Factoring Quadratic Polynomial: Now we need to factor the quadratic polynomial 5x2−14x+8. We can try to factor it by looking for two numbers that multiply to 5×8=40 and add up to −14.
Grouping and Factoring: The two numbers that satisfy these conditions are −10 and −4, since (−10)×(−4)=40 and (−10)+(−4)=−14.So we can write the quadratic as 5x2−10x−4x+8.
Common Factor Extraction: Now we can factor by grouping. We group the terms as follows: (5x2−10x)+(−4x+8).
Complete Factoring: We factor out the common factors from each group: 5x(x−2)−4(x−2).
Final Result: Since both terms have a common factor of (x−2), we can factor it out to get (5x−4)(x−2).
Final Result: Since both terms have a common factor of (x−2), we can factor it out to get (5x−4)(x−2).Now we have factored p(x) completely into linear factors: p(x)=(x+1)(5x−4)(x−2).
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