Question

[Ngô Hà Minh]

Tìm x biết 
\(\sqrt{64x+64}-\sqrt{25x+25}+\sqrt{4x+4}=20\)

Answer 1

[Lê Tuấn Nghĩa]

<=>   \(\sqrt{64\left(x+1\right)}-\sqrt{25\left(x+1\right)}+\sqrt{4\left(x+1\right)}=20\)

<=> \(8\sqrt{\left(x+1\right)}-5\sqrt{\left(x+1\right)}+2\sqrt{\left(x+1\right)}=20\)

<=>   . \(5\sqrt{\left(x+1\right)}=20\)

<=>  \(\sqrt{\left(x+1\right)}=4\)

=> x+1=16

=> x=15