1: \(A\cdot\frac43x^2y=\frac65x^3y^5\) =>\(A=\frac65x^3y^5:\frac43x^2y=\left(\frac65:\frac43\right)\cdot\left(x^3:x^2\right)\cdot\left(y^5:y\right)\) =>\(A=\left(\frac65\cdot\frac34\right)\cdot x\cdot y^4=\frac{9}{10}xy^4\) 2: \(-A\cdot\frac12xy^3=-\frac78x^3y^6\) =>\(A=\frac78x^3y^6:\frac12xy^3=\left(\frac78:\frac12\right)\cdot\left(x^3:x\right)\cdot\left(y^6:y^3\right)=\frac74x^2y^3\) 3: \(-A\cdot\left(-4xy\right)^2=\frac67x^6y^6\) =>\(-A\cdot16x^2y^2=\frac67x^6y^6\) =>\(A=-\frac67x^6y^6:16x^2y^2=\left(-\frac67:16\right)\cdot\left(x^6:x^2\right)\cdot\left(y^6:y^2\right)=-\frac{3}{56}x^4y^4\)Câu trả lời: 1: \(A\cdot\frac43x^2y=\frac65x^3y^5\) =>\(A=\frac65x^3y^5:\frac43x^2y=\left(\frac65:\frac43\right)\cdot\left(x^3:x^2\right)\cdot\left(y^5:y\right)\) =>\(A=\left(\frac65\cdot\frac34\right)\cdot x\cdot y^4=\frac{9}{10}xy^4\) 2: \(-A\cdot\frac12xy^3=-\frac78x^3y^6\) =>\(A=\frac78x^3y^6:\frac12xy^3=\left(\frac78:\frac12\right)\cdot\left(x^3:x\right)\cdot\left(y^6:y^3\right)=\frac74x^2y^3\) 3: \(-A\cdot\left(-4xy\right)^2=\frac67x^6y^6\) =>\(-A\cdot16x^2y^2=\frac67x^6y^6\) =>\(A=-\frac67x^6y^6:16x^2y^2=\left(-\frac67:16\right)\cdot\left(x^6:x^2\right)\cdot\left(y^6:y^2\right)=-\frac{3}{56}x^4y^4\)