1) (x – 3)(x + 7) - (x + 7)(x – 8) = 0; 2) (4x -9)(x - 2) + (1 - x)(x - 2) = 0;
3) 0,2x (x – 5) + 8(x – 5) = 0;
4) 7(x – 7) - (x – 7)2 = 0.​

1) х=-7

2) х₁=2; х₂=

3) х₁=-40; х₂=5

4) х=7

Пошаговое объяснение:

1)(x – 3)(x + 7) - (x + 7)(x – 8) = 0

(x+7)×(x-3-(x-8)) = 0

(x+7)×(-3+8) = 0

(x+7)×5 = 0

5х+35=0

5х=-7

х=-7

2) (4x -9)(x - 2) + (1 - x)(x - 2) = 0

(х-2)×(3х-8)=0

х-2=0         3х-8=0

х₁=2;           х₂=