Question

Answer 1

a: =>2x+5=25

=>2x=20

hay x=10

c: =>3x+1=10

=>3x=9

hay x=3

b: \(\Leftrightarrow\sqrt{x-7}=-3\)(loại)

d: =>16-7x=121

=>7x=-105

hay x=-15

Answer 2

\(\sqrt{2x+5}=5\)

\(\sqrt{2x+5}=5^2\)

\(2x+5=25\)

`2x=25-5`

`2x=20`

`x=20:2`

`x=10`

Vậy.....

_________________________________

\(\sqrt{x-7}+3=0\)

\(\sqrt{x-7}=0-3\)

\(\sqrt{x-7}=-3\)

Mà : \(\sqrt{x-7}\ge0\forall x\)

`=> x ∈ ∅`

Vậy không có giá trị nào thỏa mãn yêu cầu đề bài

_____________________________________

\(\sqrt{3x+1}=\sqrt{10}\)

\(3x+1=10\)

`3x=10-1`

`3x=9`

`x=9:3`

`x=3`

Vậy `x=3`

_________________________________

\(\sqrt{16-7x}=11\)

\(\sqrt{16-7x}=11^2\)

\(16-7x=121\)

`7x=-105`

`=> x = -105 : 7`

`x=-15`

Vậy `x=-15`

_______________________________________

`#LeMichael`