Toán Lớp 7: $\frac{5-2x}{-25}$ = $\frac{-9}{5-2x}$
Leave a reply
Register Now
Login
Lost Password
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Toán Lớp 7: $\frac{5-2x}{-25}$ = $\frac{-9}{5-2x}$
Comments ( 2 )
(5 – 2x)/(-25) = (-9)/(5 – 2x)
=> (5 – 2x)^2 = -25 . (-9)
=> (5 – 2x)^2 = 225
=> (5 – 2x)^2 = (±15)^2
=> 5 – 2x in {15; -15}
=> 2x in {-10; 20}
=> x in {-5; 10}
Vậy x in {-5; 10}
Giải đáp và lời giải
(5-2x)/(-25)=(-9)/(5-2x)
=>(5-2x).(5-2x)=(-9).(-25)
=>(5-2x)^2=225
=>\(\left[ \begin{array}{l}(5-2x)^2=15^2\\(5-2x)^2=(-15)^2\end{array} \right.\)
=>\(\left[ \begin{array}{l}5-2x=15\\5-2x=-15\end{array} \right.\)
=>\(\left[ \begin{array}{l}2x=-10\\2x=20\end{array} \right.\)
=>\(\left[ \begin{array}{l}x=-5\\x=10\end{array} \right.\)
Vậy x=-5 hoặc x=10