-2(4p - 11) + 7p = -10p - 14
-8p + 22 + 7p = -10p - 14
-p + 22 = -10p - 14
9p + 22 = -14
9p = -39
p = -4
Which property is not needed to justify any of the steps?
division property of equality
identity property of addition
addition property of equality

24p 11 7p 10p 14 8p 22 7p 10p 14 p 22 10p 14 9p 22 14 9p 39 p 4 Which property is not needed to justify any of the steps division property of equality identity class=

Respuesta :

9514 1404 393

Answer:

  (c) identity property of addition

Step-by-step explanation:

The distributive property is used to get to step 2.

The addition property is used to get to steps 4 and 5.

The division property is used to get to the last step.

The identity property of addition is not explicitly used.

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Additional comment

Actually, the identity property of addition is used wherever the addition property is used to eliminate a term. For example, when we add 10p to get to step 4, we have actually done this:

  -p +22 = -10p -14 . . . . . step 3

  -p +10p +22 = -10p +10p -14 . . . . . add 10p to both sides (addition property of equality)

  9p +22 = 0p -14 . . . . . . collect terms

  9p +22 = 0 -14 . . . . . . . zero product rule (the product is 0 when a factor is 0)

  9p +22 = -14 . . . . . . . . . identity property of addition (anything added to zero is itself)

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Similarly, the identity property of multiplication is used whenever the multiplication or division property is used to eliminate a coefficient:

  9p/9 = -36/9 . . . . division property of equality

  1p = -4 . . . . . . . . . .carry out the division

  p = -4 . . . . . . . . . . identity property of multiplication (anything multiplied by 1 is itself)