Помогите решить! x²-21x=0 2x²+28x=0 -6x+3x²=0 24x=12x²...

Question

Помогите решить!
x²-21x=0
2x²+28x=0
-6x+3x²=0
24x=12x²
81x+9x²

x²-21=0
2x²-128=0
-81+9x²
4x²=36

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пжл

Answer 1

X^2 - 21x = 0
x( x - 21 ) = 0
x= 0
x - 21 = 0
x = 21

2x^2 + 28x = 0
2x( x + 14) = 0
2x = 0
x = 0
x + 14 =0
x = - 14

- 6x + 3x^2 = 0
3x^2 - 6x = 0
3x( x - 2) = 0
3x = 0
x = 0
x - 2 = 0
x = 2

- 12x^2 + 24x = 0
x^2 - 2x = 0
x( x - 2) = 0
x = 0
x- 2 = 0
x = 2

x^2 - 21 = 0
x^2 = 21
x = +/- √21

2x^2 - 128 = 0
x^2 - 64 = 0
x^2 = 64
x = +/- 8

9x^2 - 81 = 0
x^2 - 9 = 0
x^2 = 9
x = +/- 3

4x^2 = 36
x^2 = 9
x = +/- 3