Bài 4. Tìm số nguyên x , biết:
a) |x - 2|= 0 b) |x + 3|= 1 c) -3 |4 - x|= -9 d) |2x + 1|= -2
Bài 5. Tìm số nguyên x, biết:
a) (x + 3)mũ 2 = 36 b) (x + 5)mũ 2 =100 c) (2x - 4)mũ 2 = 0 d) (x - 1)mũ 3 = 27
bài 6:Tìm x, biết:A,1/4x-1/3=-5/9;B,3,5-Ix-1/2I=0,75;C,x-1/x-5=6/7;D,(x-4)mũ 2=25;E,2 mũ x+2 mũ x-4=272;F,(x+1/2)(2/3-2x)=0
.Tìm sô nguyên x biết:a,3.(x-1)-1=26.b, |x+4|-9= (-2) mũ 3.c, 2x-5 chia hết x-1
a) 3(x - 1) - 1 = 26
=> 3x - 3 = 26 + 1
=> 3x - 3 = 27
=> 3x = 27 + 3
=> 3x = 30
=> x = 30 : 3
=> x = 10
b) |x + 4| - 9 = (-2)3
=> |x + 4| - 9 = -8
=> |x + 4| = -8 + 9
=> |x + 4| = 1
=> \(\orbr{\begin{cases}x+4=1\\x+4=-1\end{cases}}\)
=> \(\orbr{\begin{cases}x=-3\\x=-5\end{cases}}\)
Vậy ...
c) 2x - 5 \(⋮\)x - 1
<=> 2(x - 1) - 3 \(⋮\)x - 1
<=> 3 \(⋮\)x - 1
<=> x - 1 \(\in\)Ư(3) = {1; -1; 3; -3}
Lập bảng :
x - 1 | 1 | -1 | 3 | -3 |
x | 2 | 0 | 4 | -2 |
Vậy ...
a) 3×(x-1) - 1 =26
=> 3×(x-1) = 26+1
=> 3×(x-1) = 27
=> x-1 = 27:3
=> x-1 = 9
=> x= 9+1
=> x= 10
b) |x+4| - 9 = (-2)^3
= | x+4| - 9 = -8
= | x+4| = (-8)+9
= | x+4| =1
=> x+4= 1 hay x+4= (-1)
Khi x+4= 1
=> x= 1-4
=> x= -3
Khi x+4= (-1)
=> x= (-1)+4
=> x= -5
Vậy: x= -3 hoặc x= -5
Bài 4. Tìm x ∈ N biết:
a) x3 = 27 b) (2x – 1)3 = 8
c) (2x – 3)2 = 9 d) 2x + 5= 3^4 : 3^2
3^4 tức là 3 mũ 4
a, x= 3
b, ko có x thỏa mãn
c, x= 3
d, x= 2
a: x=3
b: \(2x-1=2\)
hay \(x=\dfrac{3}{2}\)
c: \(\Leftrightarrow\left[{}\begin{matrix}2x-3=3\\2x-3=-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=0\end{matrix}\right.\)
Tìm x, biết:
a) x + 15 = 34 : 3 + 8
b) 15 - (12 - x) = 22.
c) 4.(2x – 1) mũ 2 = 100
d) 2.3 mũ x – 16 = 146
Tìm x , biết :
a, x mũ 2 - 2x + 1 = 25
b, 4 x mũ 2 - ( x + 4 ) mũ 2 = 0
c, 9 - 64 x mũ 2 = 0
d, 9 ( 4 x + 3 ) mũ 2 = 16 ( 3 x - 5 ) mũ 2
a. x mũ 2 - 2x + 1 = 25
= x^2 + 2.x.1 + 1^2
= ( x + 1 ) ^2
ko bt có đúng ko nữa, mấy câu kia tui ko bt lm
Tìm x:
a) (x-20) mũ 2 -(x+1)(x+3)=-7
b) (3x+5)(4-3x)=0
c) x mũ 3 -9x=0
d)2/3x (x mũ 2 -4)=0
e) (2x+1)-x(2x+1)=0
f)(2x-1) mũ 2 -(2x+5) (2x-5) =18
g)x mũ 2 -25 =6x-9
TÌM SỐ NGUYÊN X BIẾT :
A, (-5).|x| = -75
b, ( -6 ) mũ 3 . x mũ 2 = -1944
c, ( 3 -2x ) mũ 2 = 25
d , | 9-x | = -7+ 64
e , | x+101| - ( -16 ) = (-43) . (-5)
g , 3.(x-5) -7. ( 4-x ) = x-7
h, , ( x mũ 2 -36 ) ( x mũ 2 -3 ) = 0
i, ( x mũ 2 -36 ) ( x mũ 2-3 ) < 0
k, 2 . ( 3x+12 ) > = 0
m, ( x mũ 2 + 1 ) ( 4x-24 ) < = 0
n, x mũ 2 + 5x =0
GIÚP MÌNH VỚI MỌI NGƯỜI ƠI LÀM MỘT ÍT CŨNG ĐC
\(a,\left(-5\right).\left|x\right|=-75\)
\(\left|x\right|=\frac{-75}{-5}=15\)
\(\Rightarrow\orbr{\begin{cases}x=15\\x=-15\end{cases}}\)
Vậy....
\(b,\left(-6\right)^3.x^2=-1944\)
\(-216.x^2=-1944\)
\(x^2=9\)
\(\Rightarrow x=\pm3\)
Vậy....
\(d,\left|9-x\right|=-7+64\)
\(\left|9-x\right|=57\)
\(\Rightarrow\orbr{\begin{cases}9-x=57\\9-x=-57\end{cases}\Rightarrow\orbr{\begin{cases}x=-48\\x=66\end{cases}}}\)
Vậy...
\(e,\left|x+101\right|-\left(-16\right)=\left(-43\right).\left(-5\right)\)
\(\left|x+101\right|+16=215\)
\(\left|x+101\right|=199\)
\(\Rightarrow\orbr{\begin{cases}x+101=199\\x+101=-199\end{cases}\Rightarrow\orbr{\begin{cases}x=98\\x=-300\end{cases}}}\)
Vậy..
hok tốt!!
a,\(\left(-5\right).\left|x\right|=-75\)
\(=>\left|x\right|=-75:\left(-5\right)=15\)
\(=>\orbr{\begin{cases}x=15\\x=-15\end{cases}}\)
b,\(\left(-6\right)^3.x^2=-1944\)
\(=>\frac{1944}{216}=x^2\)
\(=>x=\sqrt{\frac{1944}{216}}=3\)
CẢM ƠN MỌI NGƯỜI NHIỀU Ạ
Bài 4: Tìm x biết
a) (x-3) mũ 2 -4=0
b) (2x+3) mũ 2 - (2x+1)(2x-1)=22
c) (4x+3)(4x-3) - (4x-5) mũ 2=16
d) x mũ 3 - 9x mũ 2 + 27x - 27= -8
e) (x+1) mũ 3 - x mũ 2 nhân (x+3)=2
f) (x-2) mũ 3 - x(x-1)(x+1) + 6x mũ 2=5
a) ( x - 3 )2 - 4 = 0
<=> ( x - 3 )2 - 22 = 0
<=> ( x - 3 - 2 )( x - 3 + 2 ) = 0
<=> ( x - 5 )( x - 1 ) = 0
<=> x = 5 hoặc x = 1
b( 2x + 3 )2 - ( 2x + 1 )( 2x - 1 ) = 22
<=> 4x2 + 12x + 9 - ( 4x2 - 1 ) = 22
<=> 4x2 + 12x + 9 - 4x2 + 1 = 22
<=> 12x + 10 = 22
<=> 12x = 12
<=> x = 1
c) ( 4x + 3 )( 4x - 3 ) - ( 4x - 5 )2 = 16
<=> 16x2 - 9 - ( 16x2 - 40x + 25 ) = 16
<=> 16x2 - 9 - 16x2 + 40x - 25 = 16
<=> 40x - 34 = 16
<=> 40x = 50
<=> x = 50/40 = 5/4
d) x3 - 9x2 + 27x - 27 = -8
<=> ( x - 3 )3 = -8
<=> ( x - 3 )3 = (-2)3
<=> x - 3 = -2
<=> x = 1
e) ( x + 1 )3 - x2( x + 3 ) = 2
<=> x3 + 3x2 + 3x + 1 - x3 - 3x2 = 2
<=> 3x + 1 = 2
<=> 3x = 1
<=> x = 1/3
f) ( x - 2 )3 - x( x - 1 )( x + 1 ) + 6x2 = 5
<=> x3 - 6x2 + 12x - 8 - x( x2 - 1 ) + 6x2 = 5
<=> x3 + 12x - 8 - x3 + x = 5
<=> 13x - 8 = 5
<=> 13x = 13
<=> x = 1
a) \(\left(x-3\right)^2-4=0\)
=> \(\left(x-3\right)^2-2^2=0\)
=> \(\left(x-3-2\right)\left(x-3+2\right)=0\)
=> \(\left(x-5\right)\left(x-1\right)=0\)
=> \(\orbr{\begin{cases}x=5\\x=1\end{cases}}\)
b) \(\left(2x+3\right)^2-\left(2x+1\right)\left(2x-1\right)=22\)
=> \(\left(2x+3\right)^2-\left[\left(2x\right)^2-1^2\right]=22\)
=> \(\left(2x+3\right)^2-\left(4x^2-1\right)=22\)
=> \(\left(2x\right)^2+2\cdot2x\cdot3+3^2-4x^2+1=22\)
=> \(4x^2+12x+9-4x^2+1=22\)
=> \(12x+9+1=22\)
=> \(12x+10=22\)
=> 12x = 12
=> x = 1
c) \(\left(4x+3\right)\left(4x-3\right)-\left(4x-5\right)^2=16\)
=> \(\left(4x\right)^2-3^2-\left[\left(4x\right)^2-2\cdot4x\cdot5+5^2\right]=16\)
=> \(16x^2-9-\left(16x^2-40x+25\right)=16\)
=> \(16x^2-9-16x^2+40x-25=16\)
=> \(-9+40x-25=16\)
=> \(40x=16+25-\left(-9\right)=16+25+9=50\)
=> x = 50/40 = 5/4
d) \(x^3-9x^2+27x-27=-8\)
=> \(x^3-3\cdot x^2\cdot3+3\cdot x\cdot3^2-3^3=8\)
=> \(\left(x-3\right)^3=-8\)
=> \(\left(x-3\right)^3=\left(-2\right)^3\)
=> x - 3 = -2 => x = 1
e) \(\left(x+1\right)^3-x^2\left(x+3\right)=2\)
=> \(x^3+3x^2+3x+1-x^3-3x^2=2\)
=> \(3x+1=2\)
=> \(3x=1\)=> x = 1/3
f) \(\left(x-2\right)^3-x\left(x-1\right)\left(x+1\right)+6x^2=5\)
=> \(x^3-3\cdot x^2\cdot2+3\cdot x\cdot2^2-2^3-x\left(x^2-1\right)+6x^2=5\)
=> \(x^3-6x^2+12x-8-x^3+x+6x^2=5\)
=> \(\left(12x+x\right)-8=5\)
=> 13x = 13
=> x = 1
a) (x+3)^2-4=0
=>(x+3)^2 = 4
=>(x+3)^2 = 2^2 = (-2)^2
=>x+3 = 2 hoặc -2
=> x= -1 hoặc -5