Question

Giải pt:

a. \(\sqrt{2x\:-\:1\:}\) = \(\sqrt{15}\)

b. \(\sqrt{9-\:\left(\:x-1\right)}\) = 21

Answer 1

1,vì 2 vế pt đều dương nên bình phương 2 vế có

2x-1=15

2x=16

x=8

2, cmtt : x=-431

Answer 2

a,\(< =>2x-1=15< =>2x=14=>x=7\)

b,\(< =>9-x+1=441< =>-x=431< =>x=-431\)

Answer 3

a/ \(\sqrt{2x-1}=\sqrt{15}\)

\(\Leftrightarrow2x-1=15\Leftrightarrow2x=16\Leftrightarrow x=8\)

b/ \(\sqrt{9-\left(x-1\right)}=21\)

\(\Leftrightarrow9-x+1=441\Leftrightarrow-x=431\Leftrightarrow x=-431\)