Question

решите уравнение (√2x^2-14x+21)^2+4^2=x^2

Answer 1

( √ 2x² - 14x + 21 )² + 4² = x²
2x² - 14x + 21 + 16 = x²
x² - 14x + 47 = 0
D = 196 - 188 = 8 ; √ D = 2√2 
x1 = ( 14 + 2√2 ) : 2 = 7 + √ 2
x2 = ( 14 - 2√2 ) : 2 = 7 - √ 2