Toán Lớp 8: 1. Tính:
a, 6x ² (3x ² – 4x + 5)
b, (x – 2y) (3xy + 6y ² + x)
c, (18x^4y ³ – (23x ³y + 12x ³y ³) : (-6x ²y ³)
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Toán Lớp 8: 1. Tính:
a, 6x ² (3x ² – 4x + 5)
b, (x – 2y) (3xy + 6y ² + x)
c, (18x^4y ³ – (23x ³y + 12x ³y ³) : (-6x ²y ³)
Lm đầy đủ các bước nhaaaaa
Comments ( 2 )
a)6{x^2}.\left( {3{x^2} – 4x + 5} \right)\\
= 18{x^4} – 24{x^3} + 30{x^2}\\
b)\left( {x – 2y} \right)\left( {3xy + 6{y^2} + x} \right)\\
= 3{x^2}y + 6x{y^2} + {x^2} – 6x{y^2} – 12{y^3} – 2xy\\
= {x^2} – 12{y^3} + 3{x^2}y – 2xy\\
c)\left( {18{x^4}{y^3} – 23{x^3}y + 12{x^3}{y^3}} \right):\left( { – 6{x^2}{y^3}} \right)\\
= 18{x^4}{y^3}:\left( { – 6{x^2}{y^3}} \right) – 23{x^3}y:\left( { – 6{x^2}{y^3}} \right) + 12{x^3}{y^3}:\left( { – 6{x^2}{y^3}} \right)\\
= – 3{x^2} + \dfrac{{23x}}{{6{y^2}}} – 2x
\end{array}$