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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 \(\orbr{\begin{cases}x=3\\x=5\end{cases}}\)
a) 37 (x-15)=0
x-15 =0
x =15
b) (x-17).23=23
x-17 =1
x =1+17
x =18
c) (x-2) (x-4)=0
Th1: x-2=0
x =0+2
x =2
TH2: x-4=0
x =0+4
x =4
Vậy x=2 hoặc x=4
d) (x+12) . 53=1060
x+12 =1060:53
x+12 =20
x =20-12
x =8
e) 4 . (x-50) = 160
x-50 =160:4
x-50 =40
x =40+50
x =90
f) (17-x) : 6=2
17-x =2 . 6
17-x =12
x =17-12
x =5.
Chúc học tốt!
b. 1500(x-7)=0
x-7=0
x=7
c. (2x-4)(48-12x)=0
2x-4=0 hoặc 48-12x=0
x=2 hoặc x=4
d. (x+12)(x-1)=0
x+12=0 hoặc x-1=0
x=-12 hoặc x=1
bài 2 :
a . 128-3(x+4)=23
3(x+4)=105
x+4=35
x=31
b. [(14X+26).3+55]:5=35
(14x+26).3+55=175
(14x+26).3=120
14x+26=40
14x=14
x=1
d. 720:[41-(2X-5)]=23.5
41-(2x-5)=720:(23.5)
41-(2x-5)=144/23
2x-5=799/23
2x=914/23
x=457/23
b, 1500.(x – 7) = 0
<=>1500x-10500=0
<=>1500x=10500
<=>x=7
Vậy x=7
c,(2.x – 4).(48 – 12.x) = 0
\(\Leftrightarrow\)\(\left\{{}\begin{matrix}2x-4=0\\48-12x=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2x=4\\12x=48\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=2\\x=4\end{matrix}\right.\)
Vậy x=2 hoặc x=4
d, (x + 12).(x – 1) =0
\(\Leftrightarrow\left\{{}\begin{matrix}x+12=0\\x-1=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-12\\x=1\end{matrix}\right.\)
Vậy x=-12 hoặc x=1
Bài 2:
a) 128- 3(x+ 4) = 23
\(\Leftrightarrow\)128-(3x+12)=23
\(\Leftrightarrow\)128-3x-12=23
\(\Leftrightarrow\)116-3x=23
\(\Leftrightarrow\)3x=116-23
\(\Leftrightarrow\)3x=93
\(\Leftrightarrow\)x=31
Vậy x=31
b) [(14x+ 26). 3+ 55]: 5= 35
\(\Leftrightarrow\)(14x+ 26). 3+ 55=175
\(\Leftrightarrow\)42x+78+55=175
\(\Leftrightarrow\)42x+133=175
\(\Leftrightarrow\)42x=175-133
\(\Leftrightarrow\)42x=42
\(\Leftrightarrow\)x=1
Vậy x=1
d, 720: [41- (2x- 5)]= 23. 5
\(\Leftrightarrow\)720: 41- (2x- 5)=115
\(\Leftrightarrow\)41-(2x- 5)=720:115
\(\Leftrightarrow\)41-(2x- 5)=\(\dfrac{144}{23}\)
\(\Leftrightarrow\)2x-5=\(\dfrac{799}{23}\)
\(\Leftrightarrow\)2x=\(\dfrac{914}{23}\)
\(\Leftrightarrow\)x=\(\dfrac{457}{23}\)
Vậy x=\(\dfrac{457}{23}\)
Nếu đề là tìm x thì làm như sau :
a) (x+5).(x-4)=0
\(\Rightarrow\orbr{\begin{cases}x+5=0\\x-4=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=-5\\x=4\end{cases}}\)
Vậy x\(\in\){-5;4}
Câu b, c và d tương tự
e) 4-(27-3)=x-(13-4)
x-(13-4)=-20
x-9=-20
x=-20+9
x=-11
Vậy x=-11
f) 8-(x-10)=23-(-4+12)
8-(x-10)=15
x-10=8-15
x-10=-7
x=-7+10
x=3
Vậy x=3.
Lần sau bạn nhớ ghi yêu cầu đề bài nhé!
420 + 65 . 4 = ( x + 175 ) : 5 + 30
=> ( x + 175 ) : 5 + 30 = 420 + 45 . 4
=> ( x + 175 ) : 5 + 30 = 600
=> ( x + 175 ) : 5 = 600 - 30
=> ( x + 175 ) : 5 = 570
=> x + 175 = 570 . 5
=> x + 175 = 2850
=> x = 2850 - 175
=> x = 2675
nha bn
các câu khác tương tự nhé
nhớ ủng hộ mik nha mn
\(\text{Tìm x hở e????}\)
~~~~~~~~~
\(\text{420 + 65 . 4 = ( x + 175 ) : 5 + 30}\)
\(420+260=\left(x+175\right):5+30\)
\(680=\text{ ( x + 175 ) : 5 + 30}\)
\(\text{ ( x + 175 ) : 5 + 30=680}\)
\(\text{ ( x + 175 ) : 5 =680-30}\)
\((x+175):5=650\)
\(x+175=650:5\)
\(x+175=130\)
\(x=130-175\)
\(x=-45\)
\(\text{(32.15) : 2 = (x + 70) : 14 - 40}\)
\(480:2=\text{ (x + 70) : 14 - 40}\)
\(240\text{ = (x + 70) : 14 - 40}\)
\(\text{ (x + 70) : 14 =280}\)
\(x+70=3920\)
\(x=3920-70\)
\(x=3850\)
\(\text{x - 4867 = ( 175 . 2050 . 76) + 25 + 23}\)
\(\text{x - 4867 = ( 175 . 2050 . 76) + 48}\)
\(x-4867=27265000+48\)
\(x-4867=27265048\)
\(x=27265048+4867\)
\(x=27260015\)
\(\text{Hok giỏi nhé!~!!}\)
Lê Hoàng Khả Nhi
a, x.0 = 0
=> x = 0
b, 23( x -4) = 23
=> x -4 = 23/23
=> x -4 = 1
=> x = 1 + 4
=> x = 5
c, 12x + 40 = 76
=> 12x = 76 -40
=> 12x = 36
=> x = 36/12
=> x = 3
a) \(x.0=0\)
\(=>x\)có vô số nghiệm
b) \(23\left(x-4\right)=23\)
\(23x-92=23\)
\(23x=115\)
\(x=5\)
vậy \(x=5\)
c) \(12x+40=76\)
\(12x=36\)
\(x=3\)
vậy \(x=3\)