7^4x+2=49^x+1
^ là mũ nha
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a) \(2^3:\left|x-2\right|=2\)
\(\Leftrightarrow8:\left|x-2\right|=2\)
\(\Leftrightarrow\left|x-2\right|=8:2\)
\(\Leftrightarrow\left|x-2\right|=4\)
Xét trường hợp 1: \(x-2=4\)
\(\Rightarrow x=4+2\)
\(\Rightarrow x=6\)
Xét trường hợp 2: \(x-2=-4\)
\(\Rightarrow x=-4+2\)
\(\Rightarrow x=-\left(4-2\right)\)
\(\Rightarrow x=-2\)
Vậy \(x=6\) hoặc \(x=-2\)
b)
a) \(\left(6x-5y\right)^2=36x^2-60xy+25y^2\)
b) \(\left(4x-1\right)^2=16x^2-8x+1\)
c) \(\left(x+2\right)^2=x^2+4x+4\)
d) \(x^2-64=\left(x-8\right)\left(x+8\right)\)
e) \(4x^2-64=\left(2x-8\right)\left(2x+8\right)\)
f) \(25x^2-4=\left(5x-2\right)\left(5x+2\right)\)
g) \(\left(x+1\right)^3=x^3+3x^2+3x+1\)
h) \(\left(x-3\right)^3=x^3-9x^2+27x-27\)
k) \(x^3+8=\left(x+2\right)\left(x^2-2x+4\right)\)
l) \(x^3-125=\left(x-5\right)\left(x^2+5x+25\right)\)
y) \(27y^3-1=\left(3y-1\right)\left(9y^2+3y+1\right)\)
7A=7^2+7^3+7^4+....+7^100
A=7+7^2+7^3+....+7^99
6A=7^100-7
khi đó ta có
Trả lời:
7, 49y2 - x2 + 6x - 9
= 49y2 - ( x2 - 6x + 9 )
= ( 7y )2 - ( x - 3 )2
= ( 7y - x + 3 ) ( 7y - x - 3 )
8, sửa đề: 25x2 - 4y2 - 4y - 1
= 25x2 - ( 4y2 + 4y + 1 )
= ( 5x )2 - ( 2y + 1 )
= ( 5x - 2y - 1 ) ( 5x + 2y + 1 )
9, 4x2 - y2 + 8y - 16
= 4x2 - ( y2 - 8y + 16 )
= ( 2x )2 - ( y - 4 )2
= ( 2x - y + 4 ) ( 2x + y - 4 )
a, \(49y^2-x^2+6x-9=49y^2-\left(x-3\right)^2=\left(7y-x+3\right)\left(7y+x-3\right)\)
b, đề sai rồi bạn
c, \(4x^2-y^2+8y-16=4x^2-\left(y-4\right)^2=\left(2x-y+4\right)\left(2x+y-4\right)\)
\(\left(x-4\right)^9=49.\left(x-4\right)^7\\ =>\left(x-4\right)^9:\left(x-4\right)^7=49\\ =>\left(x-4\right)^2=49\\ =>\left[{}\begin{matrix}x-4=7\\x-4=-7\end{matrix}\right.\\ =>\left[{}\begin{matrix}x=11\\x=-3\end{matrix}\right.\)
(x - 4)9 = 49 . (x - 4)7
(x - 4)9 : (x - 4)7 = 49
(x - 4)2 = 72 = (-7)2
TH1 : TH2 :
(x - 4)2 = 72 (x - 4)2 = (-7)2
x - 4 = 7 x - 4 = -7
x = 7 + 4 x = -7 + 4
x = 11 x = -3
Vậy x = 11 Vậy x = -3
Trả lời:
1, A = 49 - 14x + x2 - y2
= ( x2 - 14x + 49 ) - y2
= ( x - 7 )2 - y2
= ( x - 7 - y ) ( x - 7 + y )
Thay x = 1; y = - 2 vào A, ta có:
A = [ 1 - 7 - ( - 2 ) ] [ 1 - 7 + ( - 2 ) ]
= ( - 4 ) ( - 8 )
= 32
2, B = 4x - 95 - 6y - 1
Thay x = y = 2 vào B, ta có:
B = 4.2 - 95 - 6.2 - 1
= - 100
\(A=49-14x+x^2-y^2=\left(x-7\right)^2-y^2=\left(x-7-y\right)\left(x-7+y\right)\)
Thay x = 1 ; y = -2 ta được : \(-4.\left(-8\right)=32\)
\(B=4x-95-6y-1\)
Thay x = y = 2 ta đươc : \(8-95-12-1=-116\)
1)
Thay x=1,y=-2 vào đa thức A có:
49-14.1+1^2+2^2
=49-14+1+4
=40
7(x - 3) - x(3 - x)
= (x - 3)(7 + x)
chỉ bt có v mà k bt có đúng k
1 ) 7 ( x - 3 ) - x ( 3 - x )
= 7 ( x - 3 ) + x ( x - 3 )
= ( x - 3 ) ( 7 + x )
2 ) 4x2 - 6x + 3 - 2x
= 4x2 - 2x - 6x + 3
= 2x ( 2x - 1 ) - 3 ( 2x - 1 )
= ( 2x - 1 ) ( 2x - 3 )
3 ) ( 4 - x ) - 4x + x2
= ( 4 - x ) - x ( 4 - x )
= ( 4 - x ) ( 1 - x )
4 ) x2 - 2xy + y2
= ( x - y )2
=>4x+2=2x+2
=>2x=0
=>x=0
\(7^{4x}+2=49^x+1\)
\(\Leftrightarrow4x+2=2\left(x+1\right)\)
\(\Leftrightarrow4x+2=2x+2\)
\(\Leftrightarrow4x-2x=2-2\)
\(\Leftrightarrow2x=0\)
\(\Leftrightarrow x=0\)