Question

Выражения/ квадрат суммы. квадрат разности 1. (2х - 1) - 2х (3х - 5) 2. 6у (у + 5) - (2у - 3)^2 3. 4 (х - 2у)^2 + 16ху

Answer 1

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Answer 2

$(2x - 1) - 2x(3x - 5) = 2x - 1 - 6x - 10x = - 14x - 1 \\ 2)6y(y + 5) - (2y - 3 {)}^{2} = 6 {y}^{2} + 30y - ((2 {y}^{2}) - 2 \times 2y \times 3 + {3}^{2} ) = \\ 6 {y}^{2} + 30y -4 {y}^{2} - 12y + 9 = 2 {y}^{2} + 18y$
$3)4( x - 2y {)}^{2} + 16xy = 4( {x}^{2} - 2x \times 2y + (2y {)}^{2} ) + 16xy = \\ 4( {x}^{2} - 4xy + 4 {y}^{2} ) + 16xy = 4 {x}^{2} - 16xy + 16 {y}^{2} + 16xy = \\ 4 {x}^{2} + 16 {y}^{2}$