(x-8)2=225
=>x-8=15 hoặc x-8=-15
=> x= 15+8 hoặc x= -15+8
=> x= 23 hoặc x=7
\(\left(x-8\right)^2=225\)
\(\left(x-8\right)^2=15^2=\left(-15\right)^2\)
\(\Rightarrow\hept{\begin{cases}x-8=15\\x-8=-15\end{cases}\Rightarrow\hept{\begin{cases}x=23\\x=-7\end{cases}}}\)
(x - 8)^2 = 225
(x - 8)^2 = 15^2
=> x - 8 = 15
x = 15 + 8
x = 23.
(x-8)\(^2\) =225
<=> x-8=15
<=>x=15+8
<=>x=23
(x-8)2 = 225
=> x2 - 82 = 225
=> x2 = 225 + 64 = 289
=> X =\(\sqrt{289}\)= 17
TÍC MÌNH NHA!
TH2 : (x - 8)^2 = (-15)^2
=> x - 8 = -15
x = -15 + 8
x = -7
Ta có:
\(\left(x-8\right)^2=225\)Vì \(225=15^2;225=\left(-15\right)^2\)
\(TH_1:x-8=15\)\(\Rightarrow x=15-8\Rightarrow x=7\)
\(TH_2:x-8=-15\)\(\Rightarrow x=-15-8\Rightarrow x=-23\)
Vậy \(x\in\left\{7;-23\right\}\)
( x-8 ) ^2=225
suy ra x-8=15
suy ra x=23