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2(4x+35)=510
4x+35=510:2
4x+35=255
4x=255-35
4x=220
x=220:4
x=55
vậy x=55
320+(413-x)=534
413-x=534-320
413-x=214
x=413-214
x=199
vậy x=199
(x-6)2=16
* (x-6)2=42 (x-6)2=(-4)2
x-6=4 x-6=-4
x=10 x=2
vậy x=10 hoặc x=2
3(9x+2)=60
9x+2=60:3
9x+2=20
9x=18
x=18:9
x=2
vậy x=2
2(4X+35)=510
4X+35=510/2
4X+35=255
4X =255-35
4X =220
X=220/4
X=55
VẬY X =55
Bài 1:
a,(2x-15):13+51=64
=> (2x-15):13=64-51
=> (2x-15):13=13
=>(2x-15)=1
=> 2x =16
=> x = 8
Vậy: x= 8
Các bạn giải nhanh hộ mình với,viết cả cách làm nha!!!!!!!
Ta co : \(\frac{\sqrt{x+1}}{\sqrt{x-3}}=\frac{\sqrt{x-3+4}}{\sqrt{x-3}}=\frac{\sqrt{x-3}}{\sqrt{x-3}}+\frac{4}{\sqrt{x-3}}\)\(=1+\frac{4}{\sqrt{x-3}}\)
De x nguyen thi \(1+\frac{4}{\sqrt{x-3}}\)nguyen
\(\Rightarrow\)\(\frac{4}{\sqrt{x-3}}\)nguyen\(\Rightarrow\)4 chia het cho \(\sqrt{x-3}\)
\(\Rightarrow\)4\(\in B\)cua \(\sqrt{x-3}\)
\(\Rightarrow\sqrt{x-3}\in\left\{4;-4;2;-2;1;-1\right\}\)
TH1 : \(\sqrt{x-3}=4\)
\(\Rightarrow x-3=16\Rightarrow x=19\)\(\Rightarrow\)chon
TH2 : \(\sqrt{x-3}=-4\) vo ly \(\Rightarrow\) loai
TH3 : \(\sqrt{x-3}=2\Rightarrow x-3=4\Rightarrow x=7\Rightarrow\)chon
TH4 : \(\sqrt{x-3}=-2\Rightarrow\)vo ly \(\Rightarrow\)chon
TH5 : \(\sqrt{x-3}=1\Rightarrow x-3=1\Rightarrow x=4\Rightarrow\)chon
TH6 : \(\sqrt{x-3}=-1\Rightarrow\)vo ly\(\Rightarrow\)loai
Vay x\(\in\){19;7;4}
bài 4 tìm X biết
a)(X-36):18=12
X-36= 12*18
X-36= 216
X= 216 + 36
X= 252
b)5X-3-2 . 52 =52 . 3
5X-3 = 52 . 3 + 2 . 52
5X-3 = 52 . ( 3+2)
5X-3 = 52 . 5
5X-3 = 52 . 5\(^1\)
5X-3 = 5\(^3\)
=> X-3=3
X= 3+3
X=6
c)X . (X - 3)=0
\(\rightarrow\) \(\orbr{\begin{cases}x=0\\x-3=0\end{cases}}\)
\(\rightarrow\orbr{\begin{cases}x=0\\x=3\end{cases}}\)
D)3X+1-32=2 .32
3X+1 = 2 .32 + 32
3X+1 = 2 .32 + 32 .1
3X+1 = 32 . ( 2+1)
3X+1 = 32 .3
3X+1 = 32 .3\(^1\)
3X+1 = 3\(^3\)
=> X+1= 3
X= 3+1
X= 4
a) \(\left(x-2\right).\left(2x-1\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-2=0\\2x-1=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=2\\2x=1\end{cases}}\Rightarrow\orbr{\begin{cases}x=2\\x=\frac{1}{2}\end{cases}}\)
b) \(\left(3x+9\right).\left(1-3x\right)=0\)
\(\Rightarrow\orbr{\begin{cases}3x+9=0\\1-3x=0\end{cases}}\Rightarrow\orbr{\begin{cases}3x=-9\\3x=1\end{cases}\Rightarrow}\orbr{\begin{cases}x=-3\\x=\frac{1}{3}\end{cases}}\)
c) (31 - 2x)3 =27
(31 - 2x)3 = 33
=> 31 - 2x = 3
2x = 31 - 3
2x = 28
x = 14
a. \(\left(x-2\right).\left(2x-1\right)=0\Leftrightarrow\orbr{\begin{cases}x-2=0\\2x-1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=2\\x=\frac{1}{2}\end{cases}}}\)
Vậy \(x=2\)hoặc \(x=\frac{1}{2}\)
b.\(\left(3x+9\right).\left(1-3x\right)=0\Leftrightarrow\orbr{\begin{cases}3x+9=0\\1-3x=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-3\\x=\frac{1}{3}\end{cases}}}\)
Vậy \(x=-3\)hoặc \(x=\frac{1}{3}\)
c.\(\left(31-2x\right)^3=-27\)
\(\Leftrightarrow\left(31-2x\right)^3=\left(-3\right)^3\)
\(\Leftrightarrow31-2x=-3\)
\(2x=34\)
\(x=17\)
d.\(\left(x-2\right).\left(7-x\right)=0\Leftrightarrow\orbr{\begin{cases}x-2=0\\7-x=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=2\\x=7\end{cases}}}\)
Vậy \(x=2\)hoặc \(x=7\)
e.\(\left(x-5\right)^5=32\)
\(\Leftrightarrow\left(x-5\right)^5=2^5\)
\(\Leftrightarrow x-5=2\Leftrightarrow x=7\)
f.\(\left(2-x\right)^4=81\)
\(\Leftrightarrow\left(2-x\right)^4=3^4\)
\(2-x=3\Leftrightarrow x=-1\)
g.\(\left|x-7\right|< 3\Leftrightarrow-3< x-7< 3\Leftrightarrow4< x< 10\)
Bài làm :
\(a,115-4x=7\)
\(4x=115-7\)
\(4x=108\)
\(x=27\)
b, Sai đề bài rồi cậu ơi
\(c,25+3.\left(x-8\right)=106\)
\(3\left(x-8\right)=106-25\)
\(3\left(x-8\right)=81\)
\(x-8=27\)
\(x=27+8\)
\(x=35\)
\(d,3^x=81\)
\(3^x=3^4\)
\(\Rightarrow x=4\)
Học tốt
a. 115-4x=7 c. 3x=81=34
Suy ra:4x=115-7=108 Suy ra:x=4
x=108:4=27
Vậy x=27
c. 25+3.(x-8)=106
3.(x-8)=106-25=81
x-8=81:3=27
x =27+8=35