Question

Name or state the postulate, property, definition, or theorem that justifies the statement.

If $a+7=b$and $b=4$, then $a+7=4$.

Short answer

The property that justifies the statement is Substitution Property.

Step-by-step solution

Step 1. State the Substitution Property.

The substitution property states that if $x=y$, then x can be substituted fory in any equation.

Step 2. Show the proof.

Here, $a+7=b$and $b=4$.

Let,

$a+7=b$ …… (1)

And

$b=4$ …… (2)

Now, substitute the value of equation (2) in equation (1), the result obtained is:

$a+7=4$.

Step 3. State the conclusion.

Therefore, the statement is justified by the substitution property.