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a: =>3[(2x-1)^2-4]=49*125:175+196=231
=>(2x-1)^2-4=77
=>(2x-1)^2=81
=>2x-1=9 hoặc 2x-1=-9
=>x=5 hoặc x=-4
b: \(\Leftrightarrow2\cdot3^x\cdot3-4^3=7^2\cdot\left(27-25\right)\)
=>\(6\cdot3^x=49\cdot2+64=162\)
=>3^x=27
=>x=3
Lời giải:
a.
$3[(2x-1)^2-4]-14^2=7^2.5^3:175=35$
$3[(2x-1)^2-4]=35+14^2=231$
$(2x-1)^2-4=231:3=77$
$(2x-1)^2=77+4=81=9^2=(-9)^2$
$\Rightarrow 2x-1=9$ hoặc $2x-1=-9$
$\Rightarrow x=5$ hoặc $x=-4$
b.
$2.3^{x+1}-4^{10}:4^7=(7^5:7^3).(3^3-5^2)=7^2.2=98$
$2.3^{x+1}-4^3=98$
$2.3^{x+1}=98+4^3=162$
$3^{x+1}=162:2=81=3^4$
$\Rightarrow x+1=4$
$\Rightarrow x=3$
a) 18.123 + 9.456.2 + 3.6
= 18.123 + 18.456 + 18
= 18 ( 123 + 456 + 1 )
= 18 . 580
= 10440
b) 1+4+7+10+...+49+52+55+58-410
= ( 58 + 1 ) . 20 : 2 - 410
= 590 - 410
= 180
a, \(\dfrac{x}{2}+\dfrac{3x}{4}=\dfrac{4}{5}\Leftrightarrow\dfrac{10x+15x}{20}=\dfrac{16}{20}\Rightarrow25x=16\Leftrightarrow x=\dfrac{16}{25}\)
b, \(\dfrac{3}{7}.\dfrac{5}{8}-\dfrac{3}{8}.\dfrac{13}{8}+\dfrac{1}{7}=\dfrac{15}{56}-\dfrac{39}{64}+\dfrac{1}{7}\)
\(=\dfrac{120}{448}-\dfrac{273}{448}+\dfrac{64}{448}=-\dfrac{89}{448}\)
1+4+7+10+...+49+52+55+58-410
=[(58-1):3+1].(1+58):2-410
=20.59:2-410
=59.10-410
=590-410
=180
chúc bạn học tốt nha
a) \(8x+56:14=60\)
\(\Rightarrow8x+4=60\)
\(\Rightarrow8x=56\)
\(\Rightarrow x=\dfrac{56}{8}\)
\(\Rightarrow x=7\)
b) Mình làm rồi nhé !
c) \(41-2^{x+1}=9\)
\(\Rightarrow2^{x+1}=41-9\)
\(\Rightarrow2^{x+1}=32\)
\(\Rightarrow2^{x+1}=2^5\)
\(\Rightarrow x+1=5\)
\(\Rightarrow x=4\)
d) \(3^{2x-4}-x^0=8\)
\(\Rightarrow3^{2x-4}-1=8\)
\(\Rightarrow3^{2x-4}=9\)
\(\Rightarrow3^{2x-4}=3^2\)
\(\Rightarrow2x-4=2\)
\(\Rightarrow2x=6\)
\(\Rightarrow x=3\)
g) \(65-4^{x+2}=2014^0\)
\(\Rightarrow65-4^{x+2}=1\)
\(\Rightarrow4^{x+2}=64\)
\(\Rightarrow4^{x+2}=4^3\)
\(\Rightarrow x+2=3\)
\(\Rightarrow x=1\)
i) \(120+2\left(4x-17\right)=214\)
\(\Rightarrow2\left(4x-17\right)=214-120\)
\(\Rightarrow2\left(4x-17\right)=94\)
\(\Rightarrow4x-17=47\)
\(\Rightarrow4x=47+17\)
\(\Rightarrow4x=64\)
\(\Rightarrow x=16\)
a: \(8x+56:14=60\)
=>8x+4=60
=>8x=60-4=56
=>x=56/8=7
b: \(5^{2x-3}-2\cdot5^2=5^2\cdot3\)
=>\(5^{2x-3}=5^2\cdot3+2\cdot5^2=5^3\)
=>2x-3=3
=>2x=6
=>x=3
c: \(41-2^{x+1}=9\)
=>\(2^{x+1}=41-9=32\)
=>x+1=5
=>x=4
d: \(3^{2x-4}-x^0=8\)
=>\(3^{2x-4}-1=8\)
=>\(3^{2x-4}=8+1=9\)
=>2x-4=2
=>2x=6
=>x=3
g: \(65-4^{x+2}=2014^0\)
=>\(65-4^{x+2}=1\)
=>\(4^{x+2}=65-1=64\)
=>x+2=3
=>x=1
i: 120+2(4x-17)=214
=>2(4x-17)=214-120=94
=>4x-17=94/2=47
=>4x=64
=>\(x=\dfrac{64}{4}=16\)
\(4^{x+3}-3.4^{x+1}=52.4^{10}\)
\(\Rightarrow4^{x+1}.\left(4^2-3\right)=52.4^{10}\)
\(\Rightarrow4^{x+1}.13=52.4^{10}\)
\(\Rightarrow4^{x+1}:4^{10}=52:13\)
\(\Rightarrow4^{x+1-10}=4\)
\(\Rightarrow x+1-10=1\)
\(\Rightarrow x=1-1+10=10\)
x=10
k mik nha
Học tốt
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