bài 1:chứng minh a. ( 2-3) (2+ 3 ) =1 b. căn bậc hai của 9- 17 x căn bậc hai của 9+ 17=8 c.( 2023+ 2022) × ( 2023- 2022) d.2 2 ×( 3-2)+(1+2 2) ²-2 6=9

Answer :

Bài ` 1 : `

` a) ( 2 - sqrt{3})( 2 + sqrt{3}) `

` = 2^2 - (sqrt{3})^2 `

` = 4 - 3 `

` = 1 `

_____________________________________________

` b) \sqrt{9-\sqrt{17}} * \sqrt{9+\sqrt{17}} `

` = \sqrt{(9-\sqrt{17})(9+\sqrt{17})}`

` = sqrt{9^2 - 17} `

` = sqrt{81 - 17} `

` = sqrt{64} `

` = 8 `

_____________________________________________

` c) ( sqrt{2023} + sqrt{2022} ) * ( sqrt{2023} - sqrt{2022} ) `

` = (sqrt{2023})^2 - (sqrt{2022)^2 `

` = 2023 - 2022 `

` = 1 `

_____________________________________________

` d) 2sqrt{2} * ( sqrt{3} - 2 ) + ( 1 + 2sqrt{2} )^2 - 2sqrt{6} `

` = 2sqrt{2} * sqrt{3} - 4 * sqrt{2} + ( 1 + 4sqrt{2} + 8 ) - 2sqrt{6} `

` = 2sqrt{6} - 4sqrt{2} + 1 + 4sqrt{2} + 8 - 2sqrt{6} `

` = 9 `