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The excersize shows you simplified expressions and asks you to justify each step
We are first given for 19. 2.1(4.5x)=(2.1 • 4.5)x
In this step the parentheses are moved so the like terms are multiplied first. This step is associative property. The next step is multiplying 2.1 and 4.5 together giving you a total of 9.45. Multiply that by x and you get 9.45 x. This step would be to solve whats inside the parentheses.
20. We are given the equivalent expressions 6+(4h+3)=(4h+3)+6
The order of the expression is moved around but what's inside the parentheses is not. This would be commutative property
Then the expression equals 4h+(3+6)
The order of the numbers are the same but the parentheses are moved.
This is once again associative property
Then in the next step the expression is equal to 4h+9
This is because what is inside the parentheses is solved 3+6=9
This would be solving whats inside the parentheses
21. Here we are asked to complete each step of simplification
This means we must fill in the blanks
So we unmultiply the variables making 8m/12mn= (2•[2]•[2m]•1)/(3•4•m•n)
And we divide the fraction so that the next expression is (2/3)•([2]/[4])•([2m]/[m])•(1/n)
The next step is to simplify the fractions so the next expression is going to be (2/3)•([1]/[2])•[2]•(1/n)
The next step is to combine like terms so we multiply 2/3 , 1/2, and 2
Multiply these together and we get 2/3 which is shown in next expression
So the next expressioj would be (2/3)•[(1/n)]
And multiplying that together gives us a final answer of [2/3n]
This is my first time answering questions on the website so i hope this helps