Question

Which expression is not equivalent to 27 − r?

a. ar−27
b. (27−r)÷0
c. (27−r)⋅1
d. −r+27

Answer 1

Option b, (27-r)÷0, is not equivalent to the expression 27 - r because division by zero is undefined and not allowed in mathematics.

Step-by-step explanation:

The expression 27 - r is equivalent to a few different mathematical expressions, but let's identify which one is not equivalent. We will evaluate the given options:

• a. ar-27: This is not equivalent as it involves a multiplication of r by some number a before subtracting 27, which changes the original expression entirely.
• b. (27-r)÷0: This expression is undefined because division by zero is not allowed in mathematics.
• c. (27-r)×1: Multiplying by 1 does not change the value of an expression, so this is equivalent to the original expression.
• d. -r+27: This is simply a rearrangement of the original expression and is equivalent.

The only option that is not equivalent to 27 - r is option b, (27-r)÷0, due to the division by zero.