Question

Answer 1

Giải các phương trình

Answer 2

6/13

Answer 3

\(\Leftrightarrow26x^3+13x-12x^2-6=0\)

\(\Leftrightarrow13x\left(2x^2+1\right)-6\left(2x^2+1\right)=0\)

\(\Leftrightarrow\left(13x-6\right)\left(2x^2+1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}13x-6=0\\2x^2+1=0\left(vn\right)\end{matrix}\right.\)

\(\Rightarrow x=\dfrac{6}{13}\)

Answer 4

b) 26x³-12x²+13x=6
\(\Leftrightarrow\)26x³-12x²+13x-6=0
\(\Leftrightarrow\)(26x³+13x)+(-12x²-6)=0
\(\Leftrightarrow\)12x(2x²+1)-6(2x²+1)=0
\(\Leftrightarrow\)(12x-6)(2x²+1)=0
\(\Leftrightarrow\)6(2x-1)(2x²+1)=0
Th1: 2x-1=0            Th2: 2x²+1=0 (vô lí)
        2x=1                           loại
          x=\(\dfrac{1}{2}\)
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