If a number is multiplied by 9 and then decreased by 9, the result is 72. What i

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Question: If a number is multiplied by 9 and then decreased by 9, the result is 72. What is the number?

Options:

Correct Answer: 8

Solution:

Let the number be x. The equation is 9x - 9 = 72. Adding 9 to both sides gives 9x = 81, so x = 81/9 = 9.

If a number is multiplied by 9 and then decreased by 9, the result is 72. What is the number?

If a number is multiplied by 9 and then decreased by 9, the result is 72. What is the number?

Correct Answer: 9

Step 1: Let the unknown number be represented by 'x'.
Step 2: According to the problem, if we multiply 'x' by 9, we get '9x'.
Step 3: Then, we decrease this result by 9, which gives us '9x - 9'.
Step 4: We know that this result equals 72, so we can write the equation: 9x - 9 = 72.
Step 5: To solve for 'x', we first add 9 to both sides of the equation: 9x - 9 + 9 = 72 + 9.
Step 6: This simplifies to: 9x = 81.
Step 7: Now, we divide both sides by 9 to find 'x': x = 81 / 9.
Step 8: Finally, we calculate 81 divided by 9, which equals 9.

Algebraic Manipulation – The question tests the ability to set up and solve a linear equation based on a word problem.
Order of Operations – Understanding the sequence of operations when solving equations, particularly addition and multiplication.