Math can be tricky sometimes. All it takes is one overlooked detail and the result is wrong. Today, you’ll find a linear equation that will test how well you know how to work with negative numbers.

Mathematical examples have a special quality – they look simple, but often hide a catch. Linear equations are one of those problems that can reveal who is working with concentration and who is just relying on a quick guess. It’s not about being a genius, it’s about being careful and following a logical step-by-step process. And that’s what you’re going to find today.

What’s in store for you today?

The equation in front of you is: -4x + 15 = 5(3x – 8) + 9. At first glance, it’s a classic problem you may have solved in high school. But it’s in these seemingly simple examples that the most common mistakes are made. Your task is clear: find the value of the variable x. Don’t forget the parentheses, the correct multiplication, and the careful addition of all the terms in the equation.

Calculate the example. ━━ Calculate the example. ( Source: Shutterstock )

The correct solution

Were you able to find the correct result? Let’s look at it together?

The correct result is x = 46/19, which is approximately 2.42.

The procedure is as follows: First, multiply the right hand side: 5(3x – 8) + 9 = 15x – 40 + 9 = 15x – 31. The equation then looks like this: -4x + 15 = 15x – 31. If you want a decimal number, the result is approximately 2.42.

Try sending this example to friends or colleagues – see who really understands maths. Problems like this are great training for the brain and help keep logical thinking in shape. Fancy another challenge? You’ll find dozens more puzzles and IQ tests on our website.