Найти значение выражения при указанных значениях переменно x=5 (x-3)(x+4)-(x+6)(x-5) Надо...

Решите задачу:

$(5 \frac{17}{29} - 3)(5 \frac{17}{29} + 4) - (5 \frac{17}{29} + 6)(5 \frac{17}{29} - 5) = \\ = ( \frac{162}{29} - 3)( \frac{162}{29} + 4) - ( \frac{162}{29} + 6)( \frac{162}{29} - 5) = \\ = ( \frac{162 - 3 \times 29}{29} )( \frac{162 + 4 \times 29}{29} ) - ( \frac{162 + 6 \times 29}{29} )( \frac{162 - 5 \times 29}{29} ) = \\ = ( \frac{162 - 87}{29} )( \frac{162 + 116}{29} ) - ( \frac{162 +174 }{29} )( \frac{162 - 145}{29} ) = \\ = \frac{75}{29} \times \frac{278}{29} - \frac{336}{29} \times \frac{17}{29} = \\ = \frac{20850}{841} - \frac{5712}{841} = \frac{15138}{841} = 18$