(х+5)^2+(х-10)^2=2х^2

(х+5)^2+(х-10)^2=2х^2 x ²+10x+25+x²-20x+100=2x² ⇔  -10x+125=0  ⇔ x=125/10    x=12,5 проверка (12,5+5)^2+(12,5-10)^2=2·12,5^2 (17,5)²+(2,5)²=306,25+6,25=312,5        2·12,5^2=2·156,25=312,5 верно