Nội dung bài giảng
Bài 70. Làm tính chia:
a) \(((25{x^5}-{\rm{ }}5{x^4} + {\rm{ }}10{x^2}){\rm{ }}:{\rm{ }}5{x^2}\);
b) \((15{x^3}{y^2}-{\rm{ }}6{x^2}y{\rm{ }}-{\rm{ }}3{x^2}{y^2}){\rm{ }}:{\rm{ }}6{x^2}y\).
Bài giải:
a) \((25{x^5}-5{x^4} +10{x^2}):5{x^2}\)
\(= (25{x^5}:5{x^2}) +(-5{x^4}:5{x^2}) +(10{x^2}:{\rm{ }}5{x^2})\)
\(= 5x^3– x^2+ 2\)
b) \((15{x^3}{y^2}-{\rm{ }}6{x^2}y{\rm{ }}-{\rm{ }}3{x^2}{y^2}){\rm{ }}:{\rm{ }}6{x^2}y\)
\( = (15{x^3}{y^2}:6{x^2}y) + (-6{x^2}y:6{x^2}y) + (-3{x^2}{y^2}:6{x^2}y)\)
\(= \frac{15}{6}xy - 1 - \frac{3}{6}y = \frac{5}{2}xy - \frac{1}{2}y - 1\).