74. Решите уравнение:
1) (х + 9)? – х(х + 8) = 1;
2) (х - 11) = (х – 7)(х – 9);

Question

Алгебра: 74. Решите уравнение: 1) (х + 9)? – х(х + 8) = 1; 2) (х - 11) = (х – 7)(х – 9);

KristiDever · Answer

1)(х + 9)^2 - х * (х + 8) = 1;

x^2 + 2 * 9 * x + 9^2 - x * x - 8 * x = 1;

x^2 + 18 * x + 81 - x^2 - 8 * x = 1;

18 * x + 81 - 8 * x = 1;

10 * x + 81 = 1;

10 * x = 1 - 81;

10 * x = -80;

x = -80/10;

x = -8/1;

x = -8;

ответ: х = -8.

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