Question

9. Calculați, aplicând formula (a - b)(a + b)=a²b² a) (2x - 1)(2x + 1) = c) (5x-2)(5x+2) = c) (2x-7)(7 + 2x)- lati aplicând formulo ..... b) (3x-4)(3x+4) ; d) (3x - 5)(5+ 3x) - f) (4x-5)(5+4x) ****** dau coroană!!!​

Answer 1

Răspuns:

$a) \: {(2x)}^{2} - {1}^{2} = {4x}^{2} - 1 \\ c) \: {(5x)}^{2} - {2}^{2} = {25x}^{2} - 4 \\ c) \: {(2x)}^{2} - {7}^{2} = {4x}^{2} - 49 \\ b) \: {(3x)}^{2} - {4}^{2} = {9x}^{2} - 16 \\ d) \: {(3x)}^{2} - {5}^{2} = {9x}^{2} - 25 \\ f) \: {(4x)}^{2} - {5}^{2} = {16x}^{2} - 25$