A number is doubled and then increased by five. The result is ninety-one. What is th original number? The number is

To find the original number, let's call it \( x \). When this number is doubled, it becomes \( 2x \). Then, when we add five to that, we have the equation \( 2x + 5 = 91 \). If we subtract 5 from both sides, we get \( 2x = 86 \). Dividing both sides by 2 gives us \( x = 43 \). So, the original number is 43! Have you ever wondered about the history of algebra? The roots of algebra can be traced back over 2,000 years to ancient Babylon. They used geometric methods, but it was the Greeks who refined these ideas, leading to more modern algebra. Fast forward to the 9th century and the Persian mathematician Al-Khwarizmi made significant contributions, even giving his name to the term "algebra"! If you're solving algebraic problems, it's common to make mistakes like forgetting to apply the order of operations or misreading the problem statement. To avoid these pitfalls, take a moment to read the question carefully, and double-check your calculations at each step. Break down the problem into smaller, manageable parts to maintain clarity and focus!