`1)`
`a)2/5-(3/4-x)=7/3`
`⇔3/4-x=2/5-7/3`
`⇔3/4-x=6/(15)-35/15`
`⇔3/4-x=-29/15`
`⇔x=3/4-(-29/15)`
`⇔x=3/4+29/15`
`⇔x=(161)/(60)`
Vậy `x=(161)/(60)`
`b)(x-5)^3=64`
`⇔(x-5)^3=4^3`
`⇔x-5=4`
`⇔x=4+5`
`⇔x=9`
Vậy `x=9`
`c)(x-3)^2=1`
`⇔(x-3)^2=1^2`
`⇔`\(\left[ \begin{array}{l}x-3=1\\x-3=-1\end{array} \right.\)
`⇔`\(\left[ \begin{array}{l}x=4\\x=2\end{array} \right.\)
Vậy `x=4` hoặc `x=2`
`d)3/5+4/5 : x=1/7`
`⇔4/5 : x=1/7 - 3/5`
`⇔4/5 : x=-16/35`
`⇔x=4/5 : (-16/35)`
`⇔x=4/5 . (-35/16)`
`⇔x=-7/4`
Vậy `x=-7/4`
`2)`
`a)M=4/3x^2y-4xy^2-x^2y+xy^2-7+xy^2`
`M=(4/3x^2y-x^2y)+(-4xy^2+xy^2+xy^2)-7`
`M=1/3x^2y-2xy^2-7`
`b)N=2x^4y-7-xy^2-2x^4y+3xy^2`
`N=(2x^4y-2x^4y)+(-xy^2+3xy^2)-7`
`N=2xy^2-7`
