Đáp án+Giải thích các bước giải:
`1)`
`(x-5)^2+3(x-5)=0`
`<=>(x-5)[(x-5)+3]=0`
`<=>(x-5)(x-5+3)=0`
`<=>(x-5)(x-2)=0`
`<=>x-5=0` hoặc `x-2=0`
`<=>x=5` hoặc `x=2`
Vậy `S=\{5;2\}`
`2)`
`(3x-9)/5=(3-x)/2`
`<=>(2(3x-9))/10=(5(3-x))/10`
`<=>2(3x-9)=5(3-x)`
`<=>6x-18=15-5x`
`<=>6x+5x=15+18`
`<=>11x=33`
`<=>x=3`
Vậy `S=\{3\}`
`3)ĐKXĐ:x\ne 2;x\ne 3`
`2/(x-2)+3/(x-3)=(3x-20)/((x-2)(x-3))`
`<=>(2(x-3))/((x-2)(x-3))+(3(x-2))/((x-2)(x-3))=(3x-20)/((x-2)(x-3))`
`=>2(x-3)+3(x-2)=3x-20`
`<=>2x-6+3x-6=3x-20`
`<=>5x-12=3x-20`
`<=>5x-3x=-20+12`
`<=>2x=-8`
`<=>x=-4(TM)`
Vậy `S=\{4\}`
