 # Section 5.1 Prime Factorization and Greatest Common Factor.

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Section 5.1 Prime Factorization and Greatest Common Factor

A prime number is a number that can only be divided by only one and itself. A composite number is a number greater than one that is not prime. Prime or composite? 37 prime 51 composite

Prime or Composite? 89 1.Prime 2.Composite 3.Both 4.Neither

1) Find the prime factorization of 84. 84=4 21 =2 2 3 7 2) Find the prime factorization of -210. -210=-1 210 =-1 30 7 = -1 6 5 7 =-1 2 3 5 7

3) Find the prime factorization of 45a 2 b 3 45a 2 b 3 = 9 5 a a b b b =3 3 5 a a b b b = 3 2 5 a a b b b Write the variables without exponents.

What is the prime factorization of 48? 1.3  16 2.3  4  4 3.2  2  3  4 4.2  2  2  2  3

The Greatest Common Factor (GCF) of 2 or more numbers is the largest number that can divide into all of the numbers. 4) Find the GCF of 42 and 60. Write the prime factorization of each number.

4) Find the GCF of 42 and 60. What prime factors do the numbers have in common? Multiply those numbers. The GCF is 2 3 = 6 6 is the largest number that can go into 42 and 60! 42 =2 3 7 60=2 2 3 5

5) Find the GCF of 40a 2 b and 48ab 4. 40a 2 b = 2 2 2 5 a a b 48ab 4 = 2 2 2 2 3 a b b b b What do they have in common? Multiply the factors together. GCF = 8ab

What is the GCF of 48 and 64? 1.2 2.4 3.8 4.16

What is the GCF of? 36 and 60 28a and 35a 2 45 and 75

Some to try: 8ab and 48a 28, 42, 56 50, 55, 60