Answer:
78
=
2
⋅
3
⋅
13
Step-by-step explanation:
78 ends with an even digit, so is divisible by 2 and we find: 78
=
2
⋅
39
39 ends with an odd digit, so is not divisible by 2
.
The digits of 39 add up to a multiple of 3
, namely 3
+
9
=
12
. So we can tell that 39 is divisible by 3
:
39
=
3
⋅
13
13 is a prime number, not divisible by any number greater than 1 or less than 13
.
So the prime factorization of
78 is:
78=
2
⋅
3
⋅
13
