Question

Rezolvati ecuatile:

a) x^2=1
b)2x^2+1=-7
c)x^2+2x^2=4x^2

Answer 1

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Answer 2

$\it a)\ \ x^2=1 \Longrightarrow \sqrt{x^2} = \sqrt1 \Longrightarrow |x| =1 \Longrightarrow x=\pm1\\ \\ \\b) \ \ 2x^2+1=-7|_{-1} \Longrightarrow 2x^2=-8|_{:2} \Longrightarrow x^2=-4 \Longrightarrow x^2 = 4\cdot(-1) \Longrightarrow \\ \\ \Longrightarrow x= \pm\sqrt{4\cdot(-1)} \Longrightarrow x= \pm2i$

$\it c) \ \ x^2+2x^2=4x^2 \Longrightarrow 0=4x^2-x^2-2x^2 \Longrightarrow 0 = x^2 \Longrightarrow \\ \\\Longrightarrow x^2=0 \Longrightarrow x = 0$