97. Решите уравнение

1) 5x (x-4) - x (3+5x) = 4

2) 7x-2x²+4=x (5-2x)

3) 2x (3x-2) - 3 (x²-4 x) = 3 x (x-7) + 2

4) 4 (2 - x²) - 3 x (x-3) = 8+9 x-7 x²

1) 5x (x-4) - x (3+5x) = 4

5x² - 20x - 3x - 5x² = 4

-23x = 4

x = - 4/23

2) 7x-2x²+4=x (5-2x)

7x - 2x² + 4 = 5x - 2x²

7x + 4 = 5x

7x - 5x = - 4

2x = - 4

x = - 2

3) 2x (3x-2) - 3 (x²-4 x) = 3 x (x-7) + 2

6x² - 4x - 3x² + 12x = 3x² - 21x + 2

3x² + 8x = 3x² - 21x + 2

8x = - 21x + 2

8x + 21x = 2

30x = 2

x = 2/30 = 1/15

4) 4 (2 - x²) - 3x (x - 3) = 8+9x-7 x²

8 - 4x² - 3x² + 9x = 8 + 9x - 7x²

8 + 9x - 7x² = 8 + 9x - 7x²

0 = 0 = > бесконечное множество решений

1)

5 х^2-20 х-3 х-5 х^2=4

-17 х=4

х=-4/17

2)

7 х-2 х^2+4=5 х-2 х^2

7 х-5 х=-4

2 х=-4

х=-2

3)

6 х^2-4 х-3 х^2-12 х=3 х^2-21 х+2

3 х^2-16 х-3 х2+21 х=2

-16 х+21 х=2

5 х=2

х=2,5

4)

8-4 х^2-3 х^2-9=8+9 х-7 х^2

-7 х^2-8-9 х+7 х^2=1

-8-9 х=1

-9 х=9

х=-1