The first step to solving this is writing an equation to put it in numbers rather than words. When a number is unknown, it is represented by a variable, usually x. But of course, the letter you use doesn't matter. The question says that an unknown number plus 9 times 6 is equal to 7 times that number minus 4. That means: (x + 9) • 6 = 7x - 4 Note that the unknown and 9 are in parenthesis. This is because it says the sum of them are being multiplied. Before you can solve, you must simplify. Using the distributive property, multiply 6 by each term in the parentheses. 6 • x = 6x 6 • 9 = 54 This leaves us with 6x + 54 = 7x - 4. Now you need to isolate the variable on one side and a known number on the other. To keep it simple, let's subtract 6x from both sides. 7x - 6x = 1x = x This gets us to 54 = x - 4 Now just add 4 to both sides to isolate the variable. 54 + 4 = 58 This means x = 58. Now just check your work! (58 + 9) • 6 = 7(58) - 4 58 + 9 = 67 67 • 6 = 402 Now the other side: 7 • 58 = 406 406 - 4 = 402
So the final answer is x, or just the unknown number in general, is 58.
