Đáp án:
`1) (x-1-\sqrt{8})(x-1+\sqrt{8})`
`2) (x-2-\sqrt{2})(x-2+\sqrt{2})`
`3) (x+3-\sqrt{6})(x+3+\sqrt{6})`
Giải thích các bước giải:
`1) x^2-2x-7`
`=x^2-2x+1-8`
`=(x^2-2x+1)-8`
`=(x^2-2.x.1+1^2)-8`
`=(x-1)^2-(\sqrt{8})^2`
`=(x-1-\sqrt{8})(x-1+\sqrt{8})`
`2) x^2-4x+2`
`=x^2-4x+4-2`
`=(x^2-4x+4)-2`
`=(x^2-2.x.2+2^2)-2`
`=(x-2)^2-(\sqrt{2})^2`
`=(x-2-\sqrt{2})(x-2+\sqrt{2})`
`3) x^2+6x+3`
`=x^2+6x+9-6`
`=(x^2+6x+9)-6`
`=(x^2+2.x.3+3^2)-6`
`=(x+3)^2-(\sqrt{6})^2`
`=(x+3-\sqrt{6})(x+3+\sqrt{6})`
Chúc bn hc tốt🥰
$\text{#LinhSad}$
