5x+5x+1+5x+2+.....+5x+2015=52019-125
Tìm số nguyên x, biết:
m) 5x = 52019 : ( 52013 - 100. 52010 )
\(\Leftrightarrow5^x=\dfrac{5^{2019}}{5^{2010}\cdot5^2}=5^7\)
hay x=7
Phân tích đa thức thành nhân tử(tách hạng tử)
1)x^2+2x-3
2)x^2-5x+6
3)x^2+7x^2+12x
4)x^2-x-12
5)3x^2+3x-36
6)5x^2-5x-10
7)3x^2-7x-6
8)4x^2+4x-3
9)8x^2-2x-3
Phân tích đa thức thành nhân tử(tách hạng tử)
1)x^2+2x-3=x^2-x+3x-3=x(x-1)+3(x-1)=(x-1)(x+3)
2)x^2-5x+6=x^2-2x-3x+6=x(x-2)-3(x-2)=(x-2)(x-3)
3)x^2+7x+12=(x+3)(x+4)
4)x^2-x-12=(x-4)(x+3)
5)3x^2+3x-36=3[(x-3)(x+4)]
6)5x^2-5x-10=5[(x-2)(x+1) ]
7)3x^2-7x-6=(x-3)(3x+2)
8)4x^2+4x-3=4x^2+6x-2x-3=(2x-1)(2x+3)
9)8x^2-2x-3=8x^2+4x-6x-3=(4x-3)(2x+1)
1: \(x^2+2x-3=\left(x+3\right)\left(x-1\right)\)
2: \(x^2-5x+6=\left(x-2\right)\left(x-3\right)\)
3: \(x^2+7x^2+12x=4x\left(2x+3\right)\)
4: \(x^2-x-12=\left(x-4\right)\left(x+3\right)\)
5: \(3x^2+3x-36=3\left(x^2+x-12\right)=3\left(x+4\right)\left(x-3\right)\)
6: \(5x^2-5x-10=5\left(x^2-x-2\right)=5\left(x-2\right)\left(x+1\right)\)
a. P=(5x−1)2+2(1−5x)(4+5x)+(5x+4)2P=(5x−1)2+2(1−5x)(4+5x)+(5x+4)2
b. Q=(x−y)3+(y+x)3+(y−x)3−3xy(x+y)
Tìm số tự nhiên x, biết
a, 2 x = 16
b, 3 x = 243
c, 5 x + 1 = 125
d, 5 x - 1 = 5
e, 4 2 x + 1 = 64
f, x 17 = x
a) x = 4
b) x = 5
c) x = 2
d) x = 2
e, x = 1
f, x = 0 hoặc x = 1
Tìm số tự nhiên x, biết
a) 2 x = 16
b) 3 x = 243
c) 5 x + 1 = 125
d) 5 x - 1 = 5
e) 4 2 x + 1 = 74
f) x 17 = x
a) x = 4
b) x = 5
c) x = 2
d) x = 2
e) x = 1
f) x = 0 hoặc x = 1.
H)5x+1=125
5x+1 = 125
5x+1 = 53
⇒ x + 1 = 3
x = 3 - 1
x = 2
Vậy x = 2
Lời giải:
$5^{x+1}=125=5^3$
$x+1=3$
$x=2$
tính
(5x-1)^2 + 2 ( 1 - 5x ) (4x+5x ) ( 5x + 4 ) ^2
\(\left(5x-1\right)^2+2\left(1-5x\right)\left(4+5x\right)+\left(5x+4\right)^2\)
\(=\left(5x-1\right)^2-2\left(5x-1\right)\left(5x+4\right)+\left(5x+4\right)^2\)
\(=\left[\left(5x-1\right)-\left(5x+4\right)\right]^2\)
\(=\left(5x-1-5x-4\right)^2\)
\(=\left(-5\right)^2\)
\(=25\)
tính (4x3+4x4-5x3+5x-2)2015+2016
với x=\(\frac{1}{2}\sqrt{\frac{\sqrt{2}-1}{\sqrt{2}+1}}\)
\(x=\dfrac{1}{2}\cdot\sqrt{\left(\sqrt{2}-1\right)^2}=\dfrac{\sqrt{2}-1}{2}\)
\(A=\left[4\cdot\left(\dfrac{\sqrt{2}-1}{2}\right)^4+4\cdot\left(\dfrac{\sqrt{2}-1}{2}\right)^3-5\cdot\left(\dfrac{\sqrt{2}-1}{2}\right)^2+5\cdot\dfrac{\sqrt{2}-1}{2}-2\right]^{2015}+2016\)
=-1,13+2016=2014,87
Tìm x biết (5x-3)2015=(5x-3)2013
(5x-3^2015=(5x-3)^2013
=>(5x-3)^2015-(5x-3)^2013=0
=>(5x-3)^2013.(5x-3)^2-(5x-3)^2013=0
=>(5x-3)^2013.[(5x-3)^2-1]=0
=>(5x-3)^2013=0=>5x-3=0=>5x=3=>x=3/5
hoặc (5x-3)^2-1=0=>(5x-3)^2=1=>....(tự làm tiếp)
Tính (5x+1)^2+(5x-1)^2-2*(5x+1)*(5x-1) tại x=1
A = (5\(x\) + 1)2 + (5\(x\) - 1)2 - 2.( 5\(x\) +1).(5\(x\) - 1) tại \(x\) = 1
Thay \(x\) = 1 vào A ta có:
A = (5.1 + 1)2 + (5.1 - 1)2 - 2.(5.1 + 1).(5.1 - 1)
A = 62 + 42 - 2.6.4
A = 36 + 16 - 48
A = 52 - 48
A = 4