(d - 7) (d + 3) - (d + 6) (d - 15) =
= d × d + d × 3 + (- 7) × d + (- 7) × 3 -
- (d × d + d × (- 15) + 6 × d + 6 × (- 15)) =
= d² + 3d + (- 7d) + (- 21) -
- (d² + (- 15d) + 6d + (- 90)) =
= d² + 3d - 7d - 21 -
- (d² - 15d + 6d - 90) =
= d² + 3d - 7d - 21 -
- d² + 15d - 6d + 90 =
= (d² - d²) + (3d - 7d + 15d - 6d) + (- 21 + 90) =
= 0 + 5d + 69 =
= 5d + 69.
При d = - 0,18,
5d + 69 = 5 × (- 0,18) + 69 = 68,1.
ответ: 68,1.
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