The equation is .
Subtraction property of equality: If a=b then .
(Subtract 8r from each side)
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(Commutative propertyof addition:
)
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(Additive inverse property:
)
(Additive identity property:
)
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(Multiply each side by negative one) \ \
(Distributive property:
)
(Product of two same signs is positive)
(Product of two different signs is negative)
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(Commutative propertyof addition:
)
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(Divide each side by 5)
(Cancel common terms)
The value of .