tìm nghiệm đa thức a)x^2-6x b)x^2-64*1/2*x+3 c)(6-3x)*(-2x+5) d)x^2+x e)3x^2+5x+2 07/10/2021 Bởi Sarah tìm nghiệm đa thức a)x^2-6x b)x^2-64*1/2*x+3 c)(6-3x)*(-2x+5) d)x^2+x e)3x^2+5x+2
Đáp án: e. \(\left[ \begin{array}{l}x = – 1\\x = – \dfrac{2}{3}\end{array} \right.\) Giải thích các bước giải: \(\begin{array}{l}a.x\left( {x – 6} \right) = 0\\ \to \left[ \begin{array}{l}x = 0\\x – 6 = 0\end{array} \right.\\ \to \left[ \begin{array}{l}x = 0\\x = 6\end{array} \right.\\c.\left( {6 – 3x} \right)\left( { – 2x + 5} \right) = 0\\ \to \left[ \begin{array}{l}6 – 3x = 0\\5 – 2x = 0\end{array} \right.\\ \to \left[ \begin{array}{l}x = 2\\x = \dfrac{5}{2}\end{array} \right.\\d.x\left( {x + 1} \right) = 0\\ \to \left[ \begin{array}{l}x = 0\\x + 1 = 0\end{array} \right.\\ \to \left[ \begin{array}{l}x = 0\\x = – 1\end{array} \right.\\e.3{x^2} + 3x + 2x + 2 = 0\\ \to 3x\left( {x + 1} \right) + 2\left( {x + 1} \right) = 0\\ \to \left( {x + 1} \right)\left( {3x + 2} \right) = 0\\ \to \left[ \begin{array}{l}x + 1 = 0\\3x + 2 = 0\end{array} \right.\\ \to \left[ \begin{array}{l}x = – 1\\x = – \dfrac{2}{3}\end{array} \right.\end{array}\) Bình luận
Đáp án:
e. \(\left[ \begin{array}{l}
x = – 1\\
x = – \dfrac{2}{3}
\end{array} \right.\)
Giải thích các bước giải:
\(\begin{array}{l}
a.x\left( {x – 6} \right) = 0\\
\to \left[ \begin{array}{l}
x = 0\\
x – 6 = 0
\end{array} \right.\\
\to \left[ \begin{array}{l}
x = 0\\
x = 6
\end{array} \right.\\
c.\left( {6 – 3x} \right)\left( { – 2x + 5} \right) = 0\\
\to \left[ \begin{array}{l}
6 – 3x = 0\\
5 – 2x = 0
\end{array} \right.\\
\to \left[ \begin{array}{l}
x = 2\\
x = \dfrac{5}{2}
\end{array} \right.\\
d.x\left( {x + 1} \right) = 0\\
\to \left[ \begin{array}{l}
x = 0\\
x + 1 = 0
\end{array} \right.\\
\to \left[ \begin{array}{l}
x = 0\\
x = – 1
\end{array} \right.\\
e.3{x^2} + 3x + 2x + 2 = 0\\
\to 3x\left( {x + 1} \right) + 2\left( {x + 1} \right) = 0\\
\to \left( {x + 1} \right)\left( {3x + 2} \right) = 0\\
\to \left[ \begin{array}{l}
x + 1 = 0\\
3x + 2 = 0
\end{array} \right.\\
\to \left[ \begin{array}{l}
x = – 1\\
x = – \dfrac{2}{3}
\end{array} \right.
\end{array}\)
Gửi bạn !