a) \(234+\left(345-x\right)=500\)
\(345-x=500-234\)
\(345-x=266\)
\(x=79\)
vay \(x=79\)
b) \(456-\left(x+23\right)=326\)
\(x+23=456-326\)
\(x+23=130\)
\(x=107\)
vay \(x=107\)
c) \(\left(5x-15\right):5=0\)
\(5x-15=0\)
\(5x=15\)
\(x=3\)
vay \(x=3\)
d) \(84-4\left(2x+1\right)=48\)
\(8x+4=84-48\)
\(8x+4=36\)
\(8x=32\)
\(x=4\)
vay \(x=4\)
e) \(\left(x-76\right).54=0\)
\(x-76=0\)
\(x=76\)
vay \(x=76\)
f) \(\left(x-3\right)\left(x+4\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-3=0\\x+4=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=3\\x=-4\end{cases}}\)
vay \(\orbr{\begin{cases}x=3\\x=-4\end{cases}}\)
g) \(\left(x-6\right)\left(x-7\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-6=0\\x-7=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=6\\x=7\end{cases}}\)
vay \(\orbr{\begin{cases}x=6\\x=7\end{cases}}\)
h) \(\left(x-2\right)\left(x-3\right)\left(x-5\right)=0\)
\(\Rightarrow x-2=0\Rightarrow x=2\)hoac \(\orbr{\begin{cases}x-3=0\\x-5=0\end{cases}\Rightarrow}\orbr{\begin{cases}x=3\\x=5\end{cases}}\)
vay \(x=2\)hoac \(\orbr{\begin{cases}x=3\\x=5\end{cases}}\)
câu a,b thì chắc bn biết
c)(5.x-15):5=0
(5.x-15) =0.5
(5.x-15) =0
5.x =0+15
5.x =15
x =15:5
x =3
d)84-4.(2.x+1)=48
4.(2.x+1)=84-48
4.(2.x+1)=36
2.x+1 =36:4
2.x+1 =9
2.x =9-1
2.x =8
x =8:2
x =4
e)(x-76).54=0
x-76 =0:54
x-76 =0
x =0+76
x =76
f) (x-3).(x+4)=0
\(\Rightarrow\orbr{\begin{cases}x-3=0\\x+4=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=3\\x=-4\end{cases}}\)
Vậy x=3 hoặc x=-4
câu g,h làm tương tự
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