Question

(54× + 83) × 21 =23 пожаалуйста

Answer 1

Как-то так
Ответ: х= -1целой 461/729

Answer 2

I'm sorry, but the equation you've provided is not correct. There seems to be a mix of numbers and variables that do not form a valid mathematical expression.

To solve an equation, it should have an equal sign (=) and valid mathematical operations involving numbers and/or variables. If you could provide a proper equation, I'd be happy to help you solve it!