Question

\(\sqrt{9+4x}\) -5 = 0

giải pt

Answer 1

\(\sqrt{9+4x}-5=0\\ \Rightarrow\sqrt{9+4x}=0+5=5\\ \Rightarrow9+4x=5^2=25\\ \Rightarrow4x=25-9=16\\ \Rightarrow x=16:4=4\)

Answer 2

`sqrt{9+4x} -5 =0`

`Đk : 9+4x >= 0 <=> x >= -9/4 `

`<=> sqrt{9+4x} =5`

`<=> 9+4x =25`

`<=> 4x = 25 -9 = 16`

`<=> x = 16/4 =4 (t//m)`

Vậy `S=4`

Answer 3

\(\sqrt{9+4x}-5=0\)

\(\Rightarrow\sqrt{9+4x}=0+5=5\)

\(\Rightarrow\)  \(9+4x=5^2=25\)

\(\Rightarrow4x=25-9=16\)

\(\Leftrightarrow x=16:4=4\)