`a)A=(x-1)^2+12`
`text{vì }(x-1)^2>0∀x`
`to(x-1)^2+12>12∀x`
`toA_(min)=12∀x`
`b) B=|x+3|+2016`
`text{vì }|x+3|>=0∀x`
`to|x+3|+2016>=2016∀x`
`toB_(min)=2016text{ khi } x =3`
`c) C=5|x-2| `
`text{vì }5|x-2|>=0∀x`
`toC_(min)=0∀x`
`\text{câu d mik chx nghĩ ra`