Toán Lớp 8: a) (6x5y
2
– 9x4y
3 + 15x3y
4
) : 3x3y
2 b) (2×3
– 21×2 + 67x – 60) : (x – 5)
c) (6×3 – 7×2 – x + 2) : (2x + 1) d) (x2 – y
2 + 6x + 9) : (x + y + 3)
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Toán Lớp 8: a) (6x5y
2
– 9x4y
3 + 15x3y
4
) : 3x3y
2 b) (2×3
– 21×2 + 67x – 60) : (x – 5)
c) (6×3 – 7×2 – x + 2) : (2x + 1) d) (x2 – y
2 + 6x + 9) : (x + y + 3)
Comments ( 1 )
a)\left( {6{x^5}{y^2} – 9{x^4}{y^3} + 15{x^3}{y^4}} \right):3{x^3}{y^2}\\
= 6{x^5}{y^2}:3{x^3}{y^2} – 9{x^4}{y^3}:3{x^3}{y^2} + 15{x^3}{y^4}:3{x^3}{y^2}\\
= 2{x^2} – 3xy + 5{y^2}\\
b)\\
\left( {2{x^3} – 21{x^2} + 67x – 60} \right):\left( {x – 5} \right)\\
= \left( {2{x^3} – 10{x^2} – 11{x^2} + 55x + 12x – 60} \right):\left( {x – 5} \right)\\
= \left( {x – 5} \right)\left( {2{x^2} – 11x + 12} \right):\left( {x – 5} \right)\\
= 2{x^2} – 11x + 12\\
c)\\
\left( {6{x^3} – 7{x^2} – x + 2} \right):\left( {2x + 1} \right)\\
= \left( {6{x^3} + 3{x^2} – 10{x^2} – 5x + 4x + 2} \right):\left( {2x + 1} \right)\\
= \left( {2x + 1} \right)\left( {3{x^2} – 5x + 2} \right):\left( {2x + 1} \right)\\
= 3{x^2} – 5x + 2\\
d)\\
\left( {{x^2} – {y^2} + 6x + 9} \right):\left( {x + y + 3} \right)\\
= \left[ {{{\left( {x + 3} \right)}^2} – {y^2}} \right]:\left( {x + y + 3} \right)\\
= \left( {x + y + 3} \right)\left( {x – y + 3} \right):\left( {x + y + 3} \right)\\
= x – y + 3
\end{array}$