There are equations that at first glance look like routine. But then the result comes in and most people stop and recalculate. This one falls into that category.

Prepare your brain for a different kind of work. Not quick decision making, not intuition – but slow, deliberate thinking, where each step depends on the one before it. Math is thankless in this regard: it won’t let you go any further until the previous step fits. And it’s this quality that makes it one of the most effective ways to train your ability to focus without taking shortcuts. Interestingly, the brain carries this habit beyond numbers – into work, conversations, decision-making. Those who occasionally pause over an equation are practicing more than they think. And whoever tells himself that he won’t get tired of such examples is usually the first to be surprised by the result.

What’s in store for you today?

In the picture you will find the equation: 5x – 3(4x – 7) + 8 = 2(3x + 2) – 5. Take a pencil and paper and follow carefully step by step.

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

The correct solution

How did you do? Did you reach the correct result or did you get lost? Now’s your chance to find out.

The correct result is x = 30/13.

Expand the parentheses: 5x – 12x + 21 + 8 = 6x + 4 – 5. Simplify both sides: -7x + 29 = 6x – 1. Convert the variables: 29 + 1 = 6x + 7x, so 30 = 13x. Result: x = 30/13.

Whoever made a mistake most likely made a mistake in unrolling the negative bracket on the left side.

Send this equation to friends or colleagues. Regular practice of such problems subtly strengthens working memory, improves the ability to concentrate, and keeps analytical thinking in shape for the long term.

More equations, puzzles and IQ challenges are waiting for you on our website – try to find out where your limits are.