The equation y - 9 + 9= -17 + 9 is an example of which property of equality?

A. Substitution property of equality
B. Addition property of equality
C. Reflexive property of equality
D. Symmetric property of equality

The equation y - 9 + 9 = -17 + 9 is an example of the addition property of equality.

The addition property of equality states that if you add the same number to both sides of an equation, the equation remains balanced. In this case, 9 is added to both sides of the equation.

To determine which property of equality is being demonstrated in the equation, let's break down the options.

A. Substitution property of equality: This property involves replacing a quantity with an equivalent quantity in an equation. It does not seem to be the case in the given equation because there is no substitution happening.

B. Addition property of equality: This property states that if you add the same number to both sides of an equation, the equation will still be true. In the given equation, we can see that 9 is being added to both sides. This aligns with the addition property of equality.

C. Reflexive property of equality: This property states that any quantity is equal to itself. It doesn't seem to be relevant to the equation.

D. Symmetric property of equality: This property states that if a = b, then b = a. It has no direct relation to the given equation.

Therefore, the correct answer is B. Addition property of equality.

D