tìm x
a,5x.(53)2=625
b,(5.x+1)2=36/49
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`(5x+1)=36/49`
`<=> 5x = 36/49-1`
`<=> 5x = -13/49`.
`<=> x = -13/245.`
Vậy `x = -13/245`.
`b, x-2/9 = 2/3`.
`<=> x = 2/3 + 2/9`
`<=> x = 8/9`.
Vậy `x = 8/9`.
c: (8x-1)^(2x+1)=5^(2x+1)
=>8x-1=5
=>8x=6
=>x=3/4
d: Sửa đề: (x-3,5)^2+(y-1/10)^4=0
=>x-3,5=0 và y-0,1=0
=>x=3,5 và y=0,1
\(\left(5x+1\right)^2=\frac{36}{49}\)
\(\left(5x+1\right)^2=\left(\frac{6}{9}\right)^2\)
\(5x+1=\frac{6}{9}\)
\(5x=\frac{6}{9}-1\)
\(x=\frac{-1}{3}:5=\frac{-1}{3}.\frac{1}{5}=\frac{-1}{15}\)
\(\left(5x+1\right)^2=\frac{36}{49}\)
(+) TH 1: 5x + 1 = 6/7
5x = 6/7 - 1
5x = -1/7
x = -1/7 : 5
x = -1 /35
(+) TH2 : 5x + 1 = - 6/7
5x = -6/7 - 1
5x = -13/7
x =-13/7 : 5
x = -13/35
a: 5x-9=5+3x
=>5x-3x=5+9
=>2x=14
=>\(x=\frac{14}{2}=7\)
b: \(2^3+0,5x=1,5\)
=>0,5x+8=1,5
=>0,5x=1,5-8=-6,5
=>\(x=-6,5:0,5=-13\)
c: \(\left(5x+1\right)^2=\frac{36}{49}\)
=>\(\left[\begin{array}{l}5x+1=\frac67\\ 5x+1=-\frac67\end{array}\right.\Rightarrow\left[\begin{array}{l}5x=\frac67-1=\frac17\\ 5x=-\frac67-1=-\frac{13}{7}\end{array}\right.\Rightarrow\left[\begin{array}{l}x=\frac17:5=\frac{1}{35}\\ x=-\frac{13}{7}:5=-\frac{13}{35}\end{array}\right.\)
d: \(\left(-\frac{3}{81}\right)^{x}=-27\)
=>\(\left(-\frac{1}{27}\right)^{x}=-27\)
=>\(x=-1\)
e: \(2^{x-1}=16\)
=>\(2^{x-1}=2^4\)
=>x-1=4
=>x=4+1=5(nhận)
( 5x + 1 )2 = 36/49
<=> ( 5x + 1 )2 = ( ±6/7 )2
<=> 5x + 1 = 6/7 hoặc 5x + 1 = -6/7
<=> x = -1/35 hoặc x = -13/35
\(\left(5x+1\right)^2=\frac{36}{49}\)
\(\Rightarrow\orbr{\begin{cases}5x+1=\frac{6}{7}\\5x+1=\frac{-6}{7}\end{cases}}\)\(\)
\(\Rightarrow\orbr{\begin{cases}5x=\frac{-1}{7}\\5x=\frac{-13}{7}\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=\frac{-1}{35}\\x=\frac{-13}{35}\end{cases}}\)
a, 5^x . (5^3)^2=625
5^x . 5^6=5^4
5^x=5^4:5^6
5^x=5^-2
=> x=-2
b)(5.x+1)2=\(\frac{36}{49}\)
\(\Rightarrow\)5.x+1=\(\sqrt{\frac{36}{49}}\)=\(\frac{6}{7}\)
\(\Rightarrow\)5.x=\(\frac{6}{7}\)-1=\(\frac{-1}{7}\)
\(\Rightarrow\)x=\(\frac{-1}{7}\):5=\(\frac{-1}{35}\)
Vậy x=\(\frac{-1}{35}\)
Chúc bạn học tốt!