(2×+7)²-4ײ=21

Решим данное уравнение.

first let's simplify the expression

(2×+7)² - 4ײ = 21

Squaring the binomial (2×+7)² we get:

(2×+7)² = (2×+7) × (2×+7) = 4ײ + 28× + 49

Now the equation becomes:

4ײ + 28× + 49 - 4ײ = 21

Simplifying further, we have:

28× + 49 = 21

Subtracting 49 from both sides:

28× = 21 - 49

28× = -28

Dividing both sides by 28:

× = -1

Ответ: решением данного уравнения является х = -1.