Toán Lớp 8: pt thành nhân tử:
a) x3– x; b) 7(x – y) – 3x(y – x); c)25×2-9y2
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Toán Lớp 8: pt thành nhân tử:
a) x3– x; b) 7(x – y) – 3x(y – x); c)25×2-9y2
Comments ( 2 )
{a){\kern 1pt} {x^3} – – x}\\
{ \Leftrightarrow x({x^2} – 1)}\\
{b)7\left( {x – – y} \right) – – 3x\left( {y – – x} \right)}\\
{{\rm{\;}} \Leftrightarrow 7\left( {x – – y} \right){\rm{ \; + \;}}3x\left( {x – y} \right)}\\
{{\rm{\;}} \Leftrightarrow (x – y)(7 + 3x)}\\
{c){\kern 1pt} 25{x^2} – 9{y^2}}\\
{{\rm{\;}} \Leftrightarrow {{(5x)}^2} – {{(3y)}^2}}\\
{ \Leftrightarrow (5x – 3y)(5x + 3y)}
\end{array}\]