Câu 1:
a: \(x^3:x^2=x^{3-2}=x\)
b: \(15x^7:3x^2=\left(\frac{15}{3}\right)\cdot x^{7-2}=5x^5\)
c: \(20x^5:12x=\left(\frac{20}{12}\right)\cdot\frac{x^5}{x}=\frac53x^4\)
f: \(12x^4y^2:\left(-9xy^2\right)=\left(-\frac{12}{9}\right)\cdot\frac{x^4}{x}\cdot\frac{y^2}{y^2}=-\frac43x^3\)
g: \(x^{10}:\left(-x\right)^8=x^{10}:x^8=x^2\)
h: \(\left(-x\right)^5:\left(-x\right)^3=\left(-x\right)^{5-3}=\left(-x\right)^2=x^2\)
Câu 2:
b: \(x^{10}:\frac{-5}{4}\left(-x\right)^8=\left(1:\frac{-5}{4}\right)\cdot\left(x^{10}:x^8\right)=-\frac45x^2\)
c: \(19x^8:\left(3x\right)^2=19x^8:9x^2=\frac{19}{9}x^6\)
d: \(\frac{25}{4}\left(-x^3\right)^5:\frac58\left(-x\right)^2\)
\(=-\frac{25}{4}\cdot x^{15}:\left(\frac58x^2\right)=\frac{-25x^{15}}{4}\cdot\frac{8}{5x^2}=\frac{-200x^{15}}{60x^2}=-\frac{10}{3}x^{13}\)
a: \(15x^2y^2:5xy^2=\left(\frac{15}{5}\right)\cdot\frac{x^2}{x}\cdot\frac{y^2}{y^2}=3x\)
c: \(5x^2y^4:10x^2y=\left(\frac{5}{10}\right)\cdot\left(\frac{x^2}{x^2}\right)\cdot\frac{y^4}{y}=\frac12y^3\)
d: \(\frac34\left(xy\right)^3:\left\lbrack-\frac12x^2y^2\right\rbrack=\frac34x^3y^3:\left(-\frac12\right)x^2y^2=-\frac32xy\)
