Toán Lớp 9: a) √x( √x – 3 ) – ( √x + 1 )( 2√x – 3 ) + 5√x( √x – 2 )
b) ( √x – 2 )( √x – 1 ) + ( √x + 3 )2√x – 3√x( √x – 4 )
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Toán Lớp 9: a) √x( √x – 3 ) – ( √x + 1 )( 2√x – 3 ) + 5√x( √x – 2 )
b) ( √x – 2 )( √x – 1 ) + ( √x + 3 )2√x – 3√x( √x – 4 )
Comments ( 1 )
a)\sqrt x \left( {\sqrt x – 3} \right) – \left( {\sqrt x + 1} \right)\left( {2\sqrt x – 3} \right) + 5\sqrt x \left( {\sqrt x – 2} \right)\\
= x – 3\sqrt x – \left( {2x – 3\sqrt x + 2\sqrt x – 3} \right) + 5x – 10\sqrt x \\
= x – 3\sqrt x – 2x + \sqrt x + 3 + 5x – 10\sqrt x \\
= 4x – 12\sqrt x + 3\\
b)\left( {\sqrt x – 2} \right)\left( {\sqrt x – 1} \right) + \left( {\sqrt x + 3} \right)2\sqrt x – 3\sqrt x \left( {\sqrt x – 4} \right)\\
= x – 3\sqrt x + 2 + 2x + 6\sqrt x – 3x + 12\sqrt x \\
= 15\sqrt x + 2
\end{array}$