Tìm x: a) 846 : [41 - (7x - 5)] = 47 b) (4x- 1)² = 25.9
a) x thuộc Ư(30) và x> 10.4 b) (4x-1)^2=25.9 c) 846:[41-(7x-5)]=47
a: \(x\in\varnothing\)
b: \(\Leftrightarrow\left[{}\begin{matrix}4x-1=15\\4x-1=-15\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=4\\x=-\dfrac{7}{2}\end{matrix}\right.\)
Tìm x: ( 4x - 1)2 = 25.9
(4x-1)^2 = 25.9 = 5.5.3.3
=> (4x-1)^2 = 15.15 = 15^2
=> 4x - 1 = 15 hoặc 4x - 1 = -15
=> 4x = 16 hoặc 4x = -14
=> x = 4 hoặc x = -7/2
Tìm x: ( 4x - 1)2 = 25.9
\(\left(4x-1\right)^2=25.9=225\\ \Leftrightarrow\left(4x-1\right)^2=15^2=\left(-15\right)^2\\ \Leftrightarrow\left[{}\begin{matrix}4x-1=15\\4x-1=-15\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}4x=16\\4x=-14\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{16}{4}=4\\x=-\dfrac{14}{4}=-\dfrac{7}{2}\end{matrix}\right.\)
\(\left(4x-1\right)^2=25\cdot9\)
\(\Rightarrow\left(4x-1\right)^2=5^2\cdot3^2\)
\(\Rightarrow\left(4x-1\right)^2=\left(5\cdot3\right)^2\)
\(\Rightarrow\left(4x-1\right)^2=15^2\)
TH1: \(4x-1=15\)
\(\Rightarrow4x=15+1\)
\(\Rightarrow4x=16\)
\(\Rightarrow x=\dfrac{16}{4}\)
\(\Rightarrow x=4\)
TH2: \(4x-1=-15\)
\(\Rightarrow4x=-15+1\)
\(\Rightarrow4x=-14\)
\(\Rightarrow x=-\dfrac{14}{4}\)
\(\Rightarrow x=-\dfrac{7}{2}\)
Tìm x:
a) (32+23).x+42.2.x=98
b) 846:[41-(2x-5) = 22+52
(3^2+2^3).x+4^2.2.x=98
(9+8).x+16.2.x=98
17.x+16.2.x=98
17.x+32.x=98
(17+32).x=98
49.x=98
x=98:49
x=2
A.(X+16/49) +(x+18/47)=(x+20/45)-1
B.(x-3/x-2)+(x-2/x-4)=-1
C.(4x-10).(x+6)=0
D.7x-1/2=5+(9-5x/6)
E.3.(7x-1)=30+9-5
F.(3x-9/x+1)-2=4x/x+1
Tìm số tự nhiên x biết:
a) 25 + 7x = 144
b) 33 - 12x = 9
c) 128 - 3(x + 4) = 23
d) 71 + (726 - 3x).5 = 2246
e) 720 : [41 - (2x + 5)] = 40
f) (10 - 4x) + 120 : 8 = 16 + 1
g) x + 9x + 7x + 5x = 2244
h) (x + 1) + (x + 2) + (x + 3) +...+ (x + 100) = 5750
i) 1 + 2 + 3 +...+ x = 500500
j) 51 + 52 + 53 +...+ x = 18825
a: Ta có: \(7x+25=144\)
\(\Leftrightarrow7x=119\)
hay x=17
b: Ta có: \(33-12x=9\)
\(\Leftrightarrow12x=24\)
hay x=2
c: Ta có: \(128-3\left(x+4\right)=23\)
\(\Leftrightarrow3\left(x+4\right)=105\)
\(\Leftrightarrow x+4=35\)
hay x=31
d: Ta có: \(71+\left(726-3x\right)\cdot5=2246\)
\(\Leftrightarrow5\left(726-3x\right)=2175\)
\(\Leftrightarrow726-3x=435\)
\(\Leftrightarrow3x=291\)
hay x=97
e: Ta có: \(720:\left[41-\left(2x+5\right)\right]=40\)
\(\Leftrightarrow41-\left(2x+5\right)=18\)
\(\Leftrightarrow2x+5=23\)
\(\Leftrightarrow2x=18\)
hay x=9
f: Ta có: \(10-4x+120:8=16+1\)
\(\Leftrightarrow4x=17-25=-8\)
hay x=-2
g: Ta có: \(x+9x+7x+5x=2244\)
\(\Leftrightarrow22x=2244\)
hay x=102
h: Ta có: \(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+100\right)=5750\)
\(\Leftrightarrow100x+5050=5750\)
\(\Leftrightarrow100x=700\)
hay x=7
a)17+x=-5 +2x
b)15-3x=-22-4x
c)47-(4x+5)=-(3x-2)
d)-58+(3-7x)=15-8x
a) 17 + x = -5 + 2x
=> x - 2x = -5 - 17
=> -x = -22
=> x = 22
b) 15 - 3x = -22 - 4x
=> -3x + 4x = -22 - 15
=> x = -37
c) 47 - (4x + 5) = -(3x - 2)
=> 47 - 4x - 5 = -3x + 2
=> -4x + 3x = 2 - 47 + 5
=> -x = -40
=> x = 40
d) -58 + (3 - 7x) = 15 - 8x
=> -58 + 3 - 7x = 15 - 8x
=> -7x + 8x =15 + 58 - 3
=> x = 70
Tìm x:
a. 2x = 16
b. 2x - 15 = 17
c. ( 4x - 1)2 = 25.9
a, b dễ :>>
a) \(2^x=16\)
\(2^x=2^4\)
\(x=4\)
b) \(2^x-15=17\)
\(2^x=17+15\)
\(2^x=32\)
\(2^x=2^5\)
\(x=5\)
Trả lời :
a, 2x = 16
=> 2x = 24
=> x = 4
b, 2x - 15 = 17
=> 2x = 32
=> 2x = 25
=> x = 5
c, (4x - 1)2 = 25 . 9
=> (4x - 1)2 = 225
=> (4x - 1)2 = \(\pm\)152
=> 4x - 1 = \(\pm\)15
\(\Rightarrow\orbr{\begin{cases}4x-1=15\\4x-1=-15\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=4\\x=\frac{-7}{2}\end{cases}}\)
c) \(\left(4x-1\right)^2=25\cdot9\)
\(\left(4x-1\right)^2=225\)
\(\Rightarrow\orbr{\begin{cases}\left(4x-1\right)^2=15^2\\\left(4x-1\right)^2=\left(-15\right)^2\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}4x-1=15\\4x-1=\left(-15\right)\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=4\\x=\frac{-7}{2}\end{cases}}\)
Vậy: ...
Tìm x,biết
a) 2x ( x-5) - 2(x2-7x+3)+3=5(4x-2)
b)7x(2x-1)-5(4x+3)=14x(x-5)