Question

tìm x
\(\sqrt{9\left(x-1\right)}=21\)
\(\sqrt{4\left(x-1\right)^2}-6=0\)
\(\sqrt{\left(x-5\right)^2}=8\)

\(\sqrt{\left(2x-1\right)^2}=3\)

\(\sqrt{\left(2x+3\right)^2}=3\)

\(\sqrt{x^2-4x+4}=2x-3\)

Answer 1

Ta có \(a,\sqrt{9(x-1)}=21 \)

<=> \(3\sqrt{x-1}=21 \)

<=> \(\sqrt{x-1}=7 \)

<=>\(x-1=49\)

<=>x=50

b, \(\sqrt{4(x-1)^2}-6=0 \)

<=>\(2|x-1|-6=0\)

<=>\(|x-1|=3\)

<=>x=4 hoặc x=-2

c,\(\sqrt{(x-5)^2}=8 \)

<=>|x-5|=8

<=>x=-3 hoặc x=13

d,\(\sqrt{(2x-1)^2}=3 \)

<=>|2x-1|=3

=> x=2 hoặc x=-1

e, \(\sqrt{(2x+3)^2}=3 \)

<=>|2x+3|=3

=>x=0 hoặc x=-3

f, \(\sqrt{x^2-4x+4}=2x-3 \)

<=>\(\sqrt{(x-2)^2}=2x-3 \)

<=>|x-2|=2x-3

Với x-2=2x-3

=>x-1=0

<=>x=1

Với 2-x=2x-3

=>x=\(\frac{5}{3}\)