Tìm x biết
A .5 mũ 2x - 3 × 5 mũ 2 = 5 mũ 2 × 3
B.2 mũ x +1- 2 mũ x = 32
Tìm x biết
5 mũ x + 1 = 125
5 mũ 2x - 3 - 2 . 5 mũ 2 = 5 mũ 2 . 3
2 mũ x = 32
giúp tớ nhé
tớ sẽ kick cho
\(5^{x+1}=125\)
\(5^{x+1}=5^3\)
\(x+1=3\)
\(x=2\)
b, \(5^{2x-3}-2.5^2=5^2.3\)
\(5^{2x-3}=5^2.\left(3+2\right)\)
\(5^{2x-3}=5^3\)
\(2x-3=3\)
\(x=3\)
c, \(2^x=32\)
\(2^x=2^5\)
\(x=5\)
Chúc em học tốt.
Bài 2: Tìm x, biết
a) (x+3) mũ 2 - (x-4)(x+8) = 1
b) (x+3)(x mũ 2 - 3x + 9) -x(x-2)(x+2) = 15
c) (x-2) mũ 2 - (x+3) mũ 2 - 4(x+1) = 5
d) (2x-3)(2x+3) - (x-1) mũ 2 - 3x(x-5) = -44
e) (x-2) mũ 3 - (x-3)(x mũ 2 + 3x + 9) + 6(x+1) mũ 2 = 49
f) 5x(x-3) mũ 2 - 5(x-1) mũ 3 + 15(x+2)(x-2) = 5
g) (x+3) mũ 3 - x(3x+1) mũ 2 + (2x+1)(4x mũ 2 - 2x + 1) - 3x mũ 2 = 42
a) \(\left(x+3\right)^2-\left(x-4\right)\left(x+8\right)=1\)
\(\Leftrightarrow\left(x^2+6x+9\right)-\left(x^2+4x-32\right)-1=0\)
\(\Leftrightarrow2x=-40\)
\(\Rightarrow x=-20\)
b) \(\left(x+3\right)\left(x^2-3x+9\right)-x\left(x-2\right)\left(x+2\right)=15\)
\(\Leftrightarrow x^3+27-x^3+4x=15\)
\(\Leftrightarrow4x=-12\)
\(\Rightarrow x=-3\)
c) \(\left(x-2\right)^2-\left(x+3\right)^2-4\left(x+1\right)=5\)
\(\Leftrightarrow\left(x^2-4x+4\right)-\left(x^2+6x+9\right)-\left(4x+4\right)=5\)
\(\Leftrightarrow-14x=14\)
\(\Rightarrow x=-1\)
d) \(\left(2x-3\right)\left(2x+3\right)-\left(x-1\right)^2-3x\left(x-5\right)=-44\)
\(\Leftrightarrow4x^2-9-\left(x^2-2x+1\right)-\left(3x^2-15x\right)=-44\)
\(\Leftrightarrow17x=-34\)
\(\Rightarrow x=-2\)
e) \(\left(x-2\right)^3-\left(x-3\right)\left(x^2+3x+9\right)+6\left(x+1\right)^2=49\)
\(\Leftrightarrow x^3-6x^2+12x-8-x^3+27+6x^2+12x+6=49\)
\(\Leftrightarrow24x=24\)
\(\Rightarrow x=1\)
f) \(5x\left(x-3\right)^2-5\left(x-1\right)^3+15\left(x+2\right)\left(x-2\right)=5\)
\(\Leftrightarrow5x^3-30x^2+45x-5x^3+15x^2-15x+5+15x^2-60=5\)
\(\Leftrightarrow30x=60\)
\(\Rightarrow x=2\)
g) \(\left(x+3\right)^3-x\left(3x+1\right)^2+\left(2x+1\right)\left(4x^2-2x+1\right)-3x^2=42\)
\(\Leftrightarrow x^3+9x^2+27x+27-9x^3-6x^2-x+8x^3+1-3x^2=42\)
\(\Leftrightarrow26x=14\)
\(\Rightarrow x=\frac{7}{13}\)
bài 1: Rút gọn giá trị biểu thức:
a) x(x+y) - y(x+y) với x=(-1/2)mũ 5 : (1/2) mũ 4 và y=8 mũ 2 : (-2) mũ 5
b) (x-y) (x mũ 2 + xy + y mũ 2) -(x+y) ( x mũ 2 - y mũ 2 ) với x-y=0
c) x mũ 3 ( x mũ 2 - y mũ 2 ) + y mũ 2 ( x mũ 3 - y mũ 3 ) với x=16 mũ 5 : 8 mũ 5 : (-2)mũ 4 và |y|=1
d) x=y=0; x = y = 1; x = 1/2; y= -3/2; x= căn 4; y= căn 9
e) 5x ( 4x mũ 2 - 2x + 1) - 2x ( 10x mũ 2 - 5x-2) với x = -3 ( -5 )
g) 12- ( 2-3b ) + 35b - 9 ( b+1 ) với b= (1/5) mũ 5 : (1/4) mũ 2
f) ( x-y) ( x mũ 2 + xy + y mũ 2 ) + ( x+y ) ( x mũ 2 -xy + y mũ 2 ) với x=2 và y = 2013 mũ 2014
bài 1: Rút gọn giá trị biểu thức:
a) x(x+y) - y(x+y) với x=(-1/2)mũ 5 : (1/2) mũ 4 và y=8 mũ 2 : (-2) mũ 5
b) (x-y) (x mũ 2 + xy + y mũ 2) -(x+y) ( x mũ 2 - y mũ 2 ) với x-y=0
c) x mũ 3 ( x mũ 2 - y mũ 2 ) + y mũ 2 ( x mũ 3 - y mũ 3 ) với x=16 mũ 5 : 8 mũ 5 : (-2)mũ 4 và |y|=1
d) x=y=0; x = y = 1; x = 1/2; y= -3/2; x= căn 4; y= căn 9
e) 5x ( 4x mũ 2 - 2x + 1) - 2x ( 10x mũ 2 - 5x-2) với x = -3 ( -5 )
g) 12- ( 2-3b ) + 35b - 9 ( b+1 ) với b= (1/5) mũ 5 : (1/4) mũ 2
f) ( x-y) ( x mũ 2 + xy + y mũ 2 ) + ( x+y ) ( x mũ 2 -xy + y mũ 2 ) với x=2 và y = 2013 mũ 2014
a)<=>
A,=(x+y)(x-y)=x^2-y^2
x=(-1/2)^5:(1/2)^4=-1/2
x^2=1/4
y=8^2/(-2)^5=-2
y^2=4
A=1/4-4=-15/4
Tìm x
a) (2x-5) mũ 2 - (2x+3).(2x-3) = 10
b) (4x-1).(x+2) - (2x+3) mũ 2 - 5.(x-1) = 9
c) (x+1) mũ 3 - (x-1) mũ 3 - 2 = 6
d) (x+2).(x mũ 2 - 2x+4 ) - (x+1).(x mũ 2 - x+1) - 3.(-x-2) = 5
a) \(\left(2x-5\right)^2-\left(2x+3\right)\left(2x-3\right)=10\Leftrightarrow\left(4x^2-20x+25\right)-\left(4x^2-9\right)-10=0\)
\(\Leftrightarrow-20x+24=0\Leftrightarrow x=\frac{6}{5}\)
b) \(\left(4x-1\right)\left(x+2\right)-\left(2x+3\right)^2-5\left(x-1\right)=9\Leftrightarrow-10x-15=0\)
\(\Leftrightarrow x=\frac{-3}{2}\)
c) \(\left(x+1\right)^3-\left(x-1\right)^3-2=6\Leftrightarrow\left(x^3+3x^2+3x+1\right)-\left(x^3-3x^2+3x-1\right)-8=0\)
\(\Leftrightarrow6x^2-6=0\Leftrightarrow x=\pm1\)
d) \(\left(x+2\right)\left(x^2-2x+4\right)-\left(x+1\right)\left(x^2-x+1\right)-3\left(-x-2\right)=5\)
\(\Leftrightarrow\left(x^3+8\right)-\left(x^3+1\right)+3x+6=5\Leftrightarrow3x+8=0\Leftrightarrow x=\frac{-8}{3}\)
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
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
1. Tìm x biết :
a) 3 mũ 2 nhân 2 mũ 5 - ( 3 nhân 6 mũ 2 - x ) = 120
b) ( x + 3 ) nhân 2 mũ 3 - 2 mũ 2 nhân 5 = 2 mũ 2 nhân 3 nhân 5
2. Tìm x biết :
a) 5 mũ x -1 - 13 = 612
b) 5 mũ x nhân 5 mũ 3 = 125
Bài 2
a) x=5
b)x=1