`c)``sqrt(x+2)=7(x>=-2)`

`=>(sqrt(x+2))^2=7^2`

`=>x+2=49`

`x=49-2`

`x=47`(tmđk)

Vậy `x=47`

`d)``2.(sqrt(x+3))^3-16=0`(x>=-3)

`2.(sqrt(x+3))^3=0+16`

`2.(sqrt(x+3))^3=16`

`(sqrt(x+3))^3=16:2`

`(sqrt(x+3))^3=8`

`(sqrt(x+3))^3=2^3`

`=>sqrt(x+3)=2`

`=>(sqrt(x+3))^2=2^2`

`=>x+3=4`

`x=4-3`

`x=1`(tmđk)

Vậy `x=1`

`e)``|sqrt(x)-1|(2x^2-8)=0(x>=0)`

`=>[(|sqrt(x)-1|=0),(2x^2-8=0):}`

`=>[(sqrt(x)-1=0),(2x^2=8):}`

`=>[(sqrt(x)=1),(x^2=4):}`

`=>[(x=1(tmđk)),(x=2(tmđk)),(x=-2(ktmđk)):}`

Vậy `x in {1;2}`

`f)``(x^2-9)(x^2-16)=0`

`=>[(x^2-9=0),(x^2-16=0):}`

`=>[(x^2=9),(x^2=16):}`

`=>[(x=3),(x=-3),(x=4),(x=-4):}`

Vậy `x in {3;-3;4;-4}`