10x²+5x=0 25-100x²=0 2x²-14=0 2x²-8=0 4x²-12=0 x²-10x=0 4x²+20x=0 2x²+x=0 3x²-27=0 4x²+20x=0

5x(2x +1) = 0 --> x = - 0.5

25 - 100x^2 = 25*(1 - 4x^2) = 25*(1 - 2x)(1+2x) --> x 1 = +0.5   x2 = - 0.5

25x^2 - 14 = 0; 25x^2 = 14 ; x^2 = 0.56 --> x = v 0.56

2x^2 - 8 = 0; 2x^2 = 8; x^2 = 4; x1= 2; x2 = -2

4x^2 - 12=0; 4x^2 = 12; x^2 = 3 ; x = v 3

x^2 - 10x = 0 ; x(x - 10) = 0--> x = 10

4x^2 + 20x = 0; 4x(x + 5)=0--> x = - 5

2x^2 + x = 0; x(x + 1) = 0 --> x = - 1

3x^2 - 27 = 0; 3(x^2 - 9)=0; 3(x-3)(x+3)=0--> x1 = 3; x2 = - 3

4x^2 + 20x = 0; 4x(x + 5) = 0; x = - 5