Contoh soal persamaan kuadrat.

Tentukan nilai $x$ yang memenuhi persamaan kuadrat berikut:

$\frac {4 - x}{\sqrt {x^2 - 8x + 32}} = \frac {3}{5}$

Jawab:

$\frac {4 - x}{\sqrt {x^2 - 8x + 32}} = \frac {3}{5}$

$\Leftrightarrow 5(4 - x) = 3(\sqrt {x^2 - 8x + 32})$

$\Leftrightarrow 25(16 - 8x + x^2) = 9(x^2 - 8x + 32)$

$\Leftrightarrow 25x^2 - 200x +400 = 9x^2 - 72x + 288$

$\Leftrightarrow 16x^2 - 128x + 112 = 0$

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$(x - 7)(x - 1) = 0$