Solve the given equation x 2 - 4x - 2 = 0 and express your answer correct to two places of decimal.

ICSE Class 10 Mathematics PYQ · 2024 Specimen · Section B

4(ii)Written · 2024 · Section B · 2024 Specimen

Solve the given equation x2 - 4x - 2 = 0 and express your answer correct to two places of decimal.

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Given, equation : x2 - 4x - 2 = 0.

By formula,

x = $\frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$

Substituting values we get :

$$\begin{aligned}\Rightarrow x = \frac{-(-4) \pm \sqrt{(-4)^2 - 4 \times 1\times -2}}{2 \times 1} \\[1em] = \frac{4 \pm \sqrt{16 + 8}}{2} \\[1em] = \frac{4 \pm \sqrt{24}}{2} \\[1em] = \frac{4 \pm 2\sqrt{6}}{2} \\[1em] = 2 \pm \sqrt{6} \\[1em] = 2 + \sqrt{6}, 2 - \sqrt{6} \\[1em] = 2 + 2.449, 2 - 2.449 \\[1em] = 4.449, -0.449\end{aligned}$$

Hence, x = 4.449 or -0.449

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