Question

Решите уравнения, ответ округлите до тысячных )))

Answer 1

Ответ:

1) x ≈ ± 2,646;  2) x ≈ ± 4,123;  3) x ≈ ± 6,782;  4) x ≈ ± 4,243.

Объяснение:

$\bold{1)} \:\:\: {x}^{2}-7=0 \\ \\ {x}^{2}=0+7 \\ \\ {x}^{2}=7 \\ \\ x=\pm \sqrt{7} \\ \\ \left[\begin{array}xx=\sqrt{7} \\x=-\sqrt{7}\end{array}\right \Rightarrow \left[\begin{array}x\bf x\approx2,646 \\\bf x\approx-2,646\end{array}\right$

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$\bold{2)} \:\:\: 2{x}^{2}-34=0 \\ \\ 2{x}^{2}=0+34 \\ \\ 2{x}^{2}=34 \\ \\ {x}^{2}=34:2 \\ \\ {x}^{2}=17 \\ \\ x=\pm\sqrt{17} \\ \\ \left[\begin{array}xx=\sqrt{17} \\x=-\sqrt{17}\end{array}\right \Rightarrow \left[\begin{array}x\bf x\approx 4,123 \\\bf x\approx-4,123\end{array}\right$

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$\bold{3)} \:\:\: 138-3x^2=0 \\ \\ -3x^2=0-138 \\ \\ -3x^2=-138 \\ \\ x^2=-138:(-3) \\ \\ x^2=46 \\ \\ x=\pm\sqrt{46} \\ \\ \left[\begin{array}xx=\sqrt{46} \\x=-\sqrt{46}\end{array}\right \Rightarrow \left[\begin{array}x\bf x\approx 6,782 \\\bf x\approx-6,782\end{array}\right$

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$\bold{4)} \:\:\: 0,3x^2-5,4=0 \\ \\ 0,3x^2=0+5,4 \\ \\ 0,3x^2 =5,4 \\ \\ x^2=5,4:0,3 \\ \\ x^2=54:3 \\ \\ x^2=18 \\ \\ x=\pm\sqrt{18} \\ \\ \left[\begin{array}xx=\sqrt{18} \\x=-\sqrt{18}\end{array}\right \Rightarrow\left[\begin{array}xx=3\sqrt{2} \\x=-3\sqrt{2}\end{array}\right \Rightarrow \left[\begin{array}x\bf x\approx 4,243 \\\bf x\approx-4,243\end{array}\right$

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