решите уравнение - (3 х-1) ^2+2 (5+х) * (х-5) + 7 х^2=3

- (3x-1) ^2+2 (5+x) * (x-5) + 7x^2=3

- (9x^2-6x+1) + 2 * (5+x) * (x-5) + 7x^2-3=0

-9x^2+6x-1+2 * (5+x) * (x-5) + 7x^2-3=0

-9x^2+6x-1 + (10+2x) * (x-5) + 7x^2-3=0

-9x^2+6x-1 + (-50+2x^2) + 7x^2-3=0

-9x^2+6x-1-50+2x^2+7x^2-3=0

-9x^2+6x-51+2x^2+7x^2-3=0

-7x^2+6x-51+7x^2-3=0

6x-51-3=0

6x-54=0

x=54/6

x=9

- (3 х-1) ^2+2 (5+х) * (х-5) + 7 х^2=3

- (9x^2-6x+1) + 2x^2-50+7x^2-3=0

-9x^2+6x-1+9x^2-53=0

6x=54

x=9