Giải PT:1, $(x^2-1993)^2-7972x+1=0$
2,$\sqrt{x^2-\frac{7}{x^2}}+\sqrt{x-\frac{7}{x^2}}=x$
Bài viết đã được chỉnh sửa nội dung bởi quan1234: 02-07-2015 - 17:25
2,$\sqrt{x^2-\frac{7}{x^2}}+\sqrt{x-\frac{7}{x^2}}=x$
$ĐKXĐ x\geq 0$
Bình phương hai vế của phương trình, ta có
$x^{2}+x-\frac{14}{x^{2}}+2\sqrt{x^{3}-7-\frac{7}{x}+\frac{49}{x^{4}}}=x^{2}$
Chuyển vế và tiếp tục bình phương , ta được
$4x^{3}+x^{2}-28=0$
Hay $x=2$( Thỏa mãn)
I learned that each mistake was probably a reflection of something that I was (or others were) doing wrong, so if I could figure out what that was, I could learn how to be more effective. I learned that wrestling with my problems, mistakes, and weaknesses was the training that strengthened me. Also, I learned that it was the pain of this wrestling that made me and those around me appreciate our successes.
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