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a, 36:(x–5) = 2 2
(x–5) = 9
x = 14
b, [3.(70–x)+5]:2 = 46
[3.(70–x)+5] = 92
70–x = 29
x = 41
c, 450:[41–(2x–5)] = 3 2 .5
41–(2x–5) = 10
2x–5 = 31
2x = 36
x = 18
d, 230+[ 2 4 +(x–5)] = 315. 2018 0
16+(x–5) = 315–230
x–5 = 85–16
x = 69+5
x = 74
e, 2 x + 2 x + 1 = 48
2 x .(2+1) = 48
2 x = 16 = 2 4
x = 4
f, 3 x + 2 + 3 x = 2430
3 x . 3 2 + 1 = 2430
3 x = 2430:10 = 243 = 3 5
x = 5
\(3^{x+2}+3^x=2430\)
\(\Rightarrow3^x\cdot\left(9+1\right)=2430\)
\(\Rightarrow3^x=2430:10=243\)
\(\Rightarrow3^x=3^5\)
\(\Rightarrow x=5\)
ti ck nha
²⁴ʱ๖ۣۜSυρɾεмε...
3^{x+2}+3^x=24303x+2+3x=2430
\Rightarrow3^x\cdot\left(9+1\right)=2430⇒3x⋅(9+1)=2430
\Rightarrow3^x=2430:10=243⇒3x=2430:10=243
\Rightarrow3^x=3^5⇒3x=35
\Rightarrow x=5⇒x=5
Em kiểm tra lại đề bài, \(3^x+3^{x+2}+3^{x+2}\) hay \(3^x+3^{x+1}+3^{x+2}\)
$\Rightarrow 3^x(1+3+3^2+3^3)=1080$
$\Rightarrow 3^x.40=1080$
$\Rightarrow 3^x=27=3^3$
$\Rightarrow x=3$
\(=3^{x+1}\left(1+3+3^2\right)+...+3^{x+10}\left(1+3+3^2\right)=\)
\(=3^x.3.13+...+3^{x+9}.3.13=\)
\(39\left(3^x+...+3^{x+9}\right)⋮39\)
Ta có: \(3^x+3^{x+2}+3^{x+3}=3^5\cdot37\)
\(\Leftrightarrow3^x\cdot\left(1+9+27\right)=3^5\cdot37\)
hay x=5
\(3^x\)\(x3^2\)\(+3^x\)\(x1=2430\)
\(3^x\)\(x9+3^x\)\(x1=2430\)
\(3^x\)\(\left(9+1\right)=2430\)
\(3^x\)\(x10=2430\)
\(3^x\)\(=2430:10=243=3^5\)
\(3^x\)\(=3^5\)
\(=>x=5\)