Which expression represents 81 decreased by an unknown number?

a. 81−a

b. 81a

c. 81÷a

d. 81 + a

Choice A

Step-by-step explanation:

The correct answer is choice A. The equation 81 - a is doing exactly what the question is asking for. It represents 81 minus an unknown number, with the unknown number being shown as a.

The answer is A. 81 - a

Step-by-step explanation: decreased is practically a synonym for subtract, so we use the symbol for subtraction (-). 81 decreased by an unknown number, which then we use a symbol to show the unknown variable, like a letter. So (a) represents the unknown number. Hence, 81 decreased by an unknown number becomes 81 - a.

false

step-by-step explanation:

the meaning of changing is to edit or make something different.

but transmitting means cause (something) to pass on from one place or person to another.

there 2 different things

answer: idk wbu

step-by-step explanation: