Đáp án:
`a)1/3a²bc-7/2a²b`
`b)3ab-3/2bc²-2b²c`
`c)2x-37/15mn²`
`d)-17/15a²bc+4`
`e)4/9a²c^4+1/60ac^4`
Giải thích các bước giải:
`a)4ab. 1/3ac-2aca-9a² .1/2b+10a². 1/5c+a²b-a²bc`
`=4/3a²bc-2a²c-9/2a²b+2a²c+a²b-a²bc`
`=(4/3a²bc-a²bc)+(-2a²c+2a²c)+(-9/2a²b+a²b)`
`=1/3a²bc-7/2a²b`
`b)2ab-2bc.c+ab+1/2c²b-4cb²+2cb.b`
`=2ab-2bc²+ab+1/2bc²-4cb²+2cb²`
`=(2ab+ab)+(-2bc²+1/2bc²)+(-4cb²+2cb²)`
`=3ab-3/2bc²-2b²c`
`c)x/3+x/6+(3x)/2-4/3mn²+0,2mn²-1(1)/3mn²`
`=x/3+x/6+(3x)/2-4/3mn²+1/5mn²-4/3mn²`
`=(x/3+x/6+(3x)/2)+(-4/3mn²+1/5mn²-4/3mn²)`
`=((2x)/6+x/6+(9x)/6)+(-20/15mn²+3/15-20/15mn²)`
`=(12x)/6-37/15mn²`
`=2x-37/15mn²`
`d)3ab. 2/5ac-2a.abc-1/3a²bc+a-5-2a+7+a+2`
`=6/5a²bc-2a²bc-1/3a²bc+a-5-2a+7+a+2`
`=(6/5a²bc-2a²bc-1/3a²bc)+(a-2a+a)+(-5+7+2)`
`=(18/15a²bc-30/15a²bc-5/15a²bc)+4`
`=-17/15a²bc+4`
`e)(2/3ac)^2 .c²-2/5a(c.c)²+2/3ac³.c-1/4ac^4`
`=4/9a²c².c²-2/5ac³+2/3ac^4-1/4ac^4`
`=4/9a²c^4-2/5ac^4+2/3ac^4-1/4ac^4`
`=4/9a²c^4+(-2/5ac^4+2/3ac^4-1/4ac^4)`
`=4/9a²c^4+(-24/60ac^4+40/60ac^4-15/60ac^4)`
`=4/9a²c^4+1/60ac^4`