Đáp án:
Giải thích các bước giải:
d) (2x-5)²=25
(2x-5)²=5²
⇒\(\left[ \begin{array}{l}2x-5=5\\2x-5=-5\end{array} \right.\)
⇒\(\left[ \begin{array}{l}2x=10\\2x =0\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x =5\\x =0\end{array} \right.\)
f)
$16x^2-(4x-5)^2=15$
⇔$16x^2-16x^2+40x-25=15$
⇔$40x=15+25$ ⇔$40x=40$
⇔$x=1$
Vậy S={1}
h) (2x+1)²-(x-1)²=0
⇔$(2x+1-x+1)(2x+1+x-1)=0$
⇔$(x+2)3x=0$ ⇔\(\left[ \begin{array}{l}x+2=0\\3x=0\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=-2\\x=0\end{array} \right.\)
Vậy S={0,-2}
