82-(11-x)2=28
=>64-(11-x)2=28
=>(11-x)2=64-28
=>(11-x)2=36
Mà: 62=36 và (-6)2=36
=>11-x=6 hoặc 11-x= -6
=>x=5 hoặc x= 17
82 - (11 - x)2 = 28
64 - (11 - x)2 = 28
(11 - x)2 = 64 - 28
(11 - x)2 = 36
(11 - x)2 = 62
=> 11 - x = 6
x = 11 - 6
x = 5
\(\left(11-x\right)^2=8^2-28=4\left(16-7\right)=4.9=\left(2.3\right)^2\)
\(11-x=+-6\)
x=11+-6
\(\orbr{\begin{cases}x=17\\x=5\end{cases}}\)
\(8^2-\left(11-x\right)^2=28\)
\(x\in\left(-\infty;\infty\right)\)
\(-x^2+22x-57=28\)
\(-x^2+22x-85=0\)
\(D=b^2-4ac\)
\(22^2-4.85=144\)
\(x_{1,2}=\frac{-b+\sqrt{D}}{2a}=-\frac{-2+\sqrt{144}}{2}\)
\(x=5\)
\(x=17\)
82-(11-x)2 = 28
64-(11-x)2 = 28
(11-x)2 = 64-28
(11-x)2 = 36
(11-x)2=
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