Question

(8d-13r) 2 - (15r-19d) 2=?

Answer 1

Ответ:

$= 2(8d - 13r) - 2(15r - 19d) \\ 2(8d - 13r - (15r - 19d)) \\ 2(8d - 13r - 15r + 19d) = 2(27d - 28r)$

Answer 2

To simplify the given expression, let's expand and simplify each term separately:

Expanding (8d - 13r)²: (8d - 13r)² = (8d - 13r) * (8d - 13r) = 64d² - 104dr - 104dr + 169r² = 64d² - 208dr + 169r²

Expanding (15r - 19d)²: (15r - 19d)² = (15r - 19d) * (15r - 19d) = 225r² - 285dr - 285dr + 361d² = 361d² - 570dr + 225r²

Now let's substitute these expanded forms back into the original expression:

(8d - 13r)² - (15r - 19d)² = (64d² - 208dr + 169r²) - (361d² - 570dr + 225r²) = 64d² - 208dr + 169r² - 361d² + 570dr - 225r² = (64d² - 361d²) + (-208dr + 570dr) + (169r² - 225r²) = -297d² + 362dr - 56r²

Therefore, the simplified expression is -297d² + 362dr - 56r².