Giúp mk với ạ

`d,D = 4x^2 - 3x + 12`
`=4(x^2 - 3/4 x + 3)`
`=4[x^2 - 2.x. 3/8 + (3/8)^2 + 183/64]`
`=4(x-3/8)^2 + 183/16`
Do `4(x-3/8)^2 >=0AAx`
`=>D>=183/16 AAx`
Dấu `"="` xảy ra `<=>4(x-3/8)^2 =0`
`<=>x-3/8=0`
`<=>x=3/8`
`e,E = 3x^2 - 2x + 3`
`=3(x^2 -2/3 x +1)`
`=3[x^2 - 2 . x . 1/3  + (1/3)^2 + 8/9]`
`=3(x-1/3)^2 + 8/3`
Do `3(x-1/3)^2 >=0AAx`
`=>E>=8/3 AAx`
Dấu `"="` xảy ra `<=>3(x-1/3)^2 =0`
`<=>x-1/3=0`
`<=>x=1/3`
`f,F=x^2  - 7x - 2`
`=x^2 - 2 .x . 7/2 + (7/2)^2 - 57/4`
`=(x-7/2)^2 - 57/4`
Do `(x-7/2)^2 >=0 AAx`
`=>F>= -57/4 AAx`
Dấu `"="` xảy ra `<=>(x-7/2)^2 = 0`
`<=>x-7/2=0`
`<=>x=7/2`
`g,G = x^2 + y^2 - 6x + y -5 `
`=(x^2 - 2 . x . 3 + 3^2) + [y^2 + 2 . y . 1/2 + (1/2)^2] - 57/4`
`=(x-3)^2 + (y+1/2)^2 - 57/4`
Do `{((x-3)^2>=0AAx),((y+1/2)^2 >=0AAy):}`
`=>G>=-57/4AAx;y`
Dấu `"="` xảy ra `<=>{((x-3)^2 = 0),((y+1/2)^2 = 0):}`
`<=>{(x-3=0),(y+1/2=0):} <=>{(x=3),(y=-1/2):}`