Which property was used to simplify the expression of 3c+9+4c=3c+4c+9

Which property was used to simplify the expression?

3c+9+4c=3c+4c+9

distributive property

commutative property

associative property

inverse property

Commutative property of addition is used

Given that,

3c + 9 + 4c = 3c + 4c + 9

We have to find the property used here

The property used is commutative property of addition

Definition:

Commutative property of addition means that numbers can be added in any order and we will still get the same answer

This means that,

a + b + c = a + c + b

It doesnt matter which is added first, we will still get the same answer

Therefore,

3c + 9 + 4c = 3c + 4c + 9

7c + 9 = 7c + 9

Thus commutative property of addition is used

1,407.5 hours

step-by-step explanation:

we first convert all the time to hours and then sum them up.

there are 24 hours in 1 day, in 58 days, there are 24 x 58 = 1,392 hours.

there are 60 minutes in 1 hour, thus, 30 minutes will be equivalent to 30 / 60 = 0.5 hours.

therefore, the number of hours it will take mercury to complete a full rotation is 1,392 + 15 + 0.5 = 1,407.5 hours