Use the divisibility rules to help determine the prime factorization of the number below. 85
A) $7 \cdot 17$
B) $5 \cdot 17$
C) $3 \cdot 5 \cdot 17$
D) $3 \cdot 17$
E) none of these

Question

Quizplus · Accepted Answer

85 is not divisible by 2, 3, 4, 6, 8, or 9. To check for divisibility by 5, we just need to look at the units digit, which is 5. Since 5 is a factor of 85, the number is divisible by 5. Therefore, we can divide 85 by 5 to get 17. We cannot divide 17 any further, so the prime factorization of 85 is 5 times 17, or 5 · 17 = 85.

Use the Divisibility Rules to Help Determine the Prime Factorization 7⋅177 \cdot 177⋅17

Use the Divisibility Rules to Help Determine the Prime Factorization $7 \cdot 17$