Đáp án`+`Giải thích các bước giải:

C9:

`x^2 + 2x - 2 = 0`

`x^2 + 2x + 1 = 3`

`(x + 1)^2 = 3`

`x + 1 = ±\sqrt{3}`

`x = \sqrt{a3 - 1; -\sqrt{3} - 1`

Vậy ...

C10:

`4x^2 + 9x - 13 = 0`

`(4x^2 + 2 . 2x . 9/4 + 81/16) =289/16`

`(2x + 9/4)^2 = 289/16`

`2x + 9/4 = ±17/4`

TH1: `2x + 9/4 = 17/4`

        `2x           = 2`

          `x           = 1`

TH2: `2x + 9/4 = -17/4`

        `2x           = 13/2`

          `x           = 13/4`

Vậy ...

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{\text{a}}$$\color{#8c4ebd}{\text{t}}$$\color{#B592D6}
{\text{h}}$$\color{#ceaedf}{\text{s}}$꧂