What property is in (6+3)+21=6+(3+21)

This is called the Associative Property of Addition.

In short, associative property of addition states that the quantity of an additive expression is going to be the same no matter how the expression is grouped. In this case, it doesn't matter whether 6+3 is added first or 3+21 is added first because they will end up with the same quantity.

2 2/3 hours duhh silly

step-by-step explanation:

x = 2

step-by-step explanation:

if sr parallel to ba then the sides bc and ac are in proportion, that is

= ← substitute values

= ( cross- multiply )

27x = 6(4x + 1)

27x = 24x + 6 ( subtract 24x from both sides )

3x = 6 ( divide both sides by 3 )

x = 2