1)(x-5)^2+(x+4)^2=2x^2 2)5x^2-12x+7=0 3)x^2-121=0 4)5x^2+20x=0 5)(x-2)(-x-1)=0

Question

1)(x-5)^2+(x+4)^2=2x^2 2)5x^2-12x+7=0 3)x^2-121=0 4)5x^2+20x=0 5)(x-2)(-x-1)=0

Answer 1

1) x^2-10x+25+x^2+8x+16=2x^2    

  2x = 41

  x = 20,5

2) 5x^2-12x+7=0

   D= 144 - 140 = 4

  x1,2 = (12+-2)/10

  x1 = 1,4 x2 = 1

3) x^2-121=0

   x^2=121

   x1 = 11

   x2 = -11

4) 5x^2+20x=0

  5x(x+4)=0

 x=0 или x= 4

5) (x-2)(-x-1)=0

   x=2 или x= -1

вроде так