a) 4(x + 1/2)^2=100
(x + 1/2)^2 = 100 : 4
(x + 1/2)^2 = 25
(x + 1/2)^2 = 5^2
=> x + 1/2 =5
x = 5 - 1/2
x = 9/2
vậy x= 9/2
a: \(4\left(x+\dfrac{1}{2}\right)^2=100\)
=>\(\left(x+\dfrac{1}{2}\right)^2=25\)
=>\(\left[{}\begin{matrix}x+\dfrac{1}{2}=5\\x+\dfrac{1}{2}=-5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{9}{2}\\x=-\dfrac{11}{2}\end{matrix}\right.\)
b: ĐKXĐ: x<>-5/2
\(\dfrac{2x+5}{-3}=\dfrac{-27}{2x+5}\)
=>\(\left(2x+5\right)^2=\left(-3\right)\cdot\left(-27\right)=81\)
=>\(\left[{}\begin{matrix}2x+5=9\\2x+5=-9\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}2x=4\\2x=-14\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}x=2\left(nhận\right)\\x=-7\left(nhận\right)\end{matrix}\right.\)
