Section 5.1
Greatest Common Factor for Monomials
Find the greatest common factor for each group of monomials.
40. 16x²z, 40xz², 72x³
Section 5.2
Factoring a Difference of Two Squares
Factor each polynomial.
16. 9a² - 64b²
Section 5.3
Factoring with Two Variables
Factor each polynomial.
64. h²- 9hs + 9s²
Section 5.4
The ac Method
Factor each trinomial using the ac method.
26. 21x² + 2x - 3
Section 5.5
Factoring a Difference of Two Fourth Powers
Factor each polynomial completely.
36. m⁴ - n⁴
Section 5.6
The Zero Factor Property
Solve by factoring.
32. 2w(4w + 1) = 1
Discussion Questions
DQ 1: How would you use this procedure to determine if a given polynomial is prime, that is, determine that it cannot be factored into a product of two linear polynomials (note pps 321 and 327 of the text, Prime Polynomials)?
(7) P(x) = ax2 + bx + c, where a ≠ 1,
DQ 2: Given the prime factorization of an integer, how can you determine if our integer is a perfect square?
DQ 3: In the procedure for determining the prime factorization of an integer, why is it that we need not consider dividing by prime factors greater than the square root of that integer?
DQ 4: In the prime factorization of an integer, what is the maximum number of prime factors greater than the square root of that integer? If there is a prime factor greater than the square root of that integer, can the integer be a perfect square?
Note the polynomial form P(x) = x2 - a. And, note that the two linear factors ( x + sqrt(a) ) ( x - sqrt(a) ), when multiplied together, yield
( x + sqrt(a) ) ( x - sqrt(a) ) = x2 - a.
Consequently, we note that an equation of the form
x2 - a = 0
can be factored as
( x + sqrt(a) ) ( x - sqrt(a) ) = 0,
giving the two zeros of our equation
x = sqrt(a), -sqrt(a).
Team Exercise Two:
Consider the quadratic expression representing displacement of an object thrown toward earth at an initial velocity of 32 ft / sec from a height of 128 ft.
h(t) = -16t2 - 32t + 128
For this expression, determine the GCF (Greatest Common Factor) of our three coefficients and, as in exercise one, express h(t) as a product of this GCF and a resulting trinomial. Factor our resulting trinomial into a product of two binomials, thus completely factoring our expression h(t). What does a solution, or zero, of the equation
-16t2 - 32t + 128 = 0
represent? Determine the two solutions.