Bài 1.
a, (x-2)-15=65
x-2=65+15
x-2=80
x=80+2
x=2
b, 115-2\(\times\)(x-3)=35
2\(\times\)(x-3)=115-35
2\(\times\)(x-3)=70
x-3=70:2
x-3=35
x=35+5
x=38
c, 35+2\(\times\)(x-3)=65
2\(\times\)(x-3)=65-35
2\(\times\)(x-3)=30
x-3=30:2
x-3=15
x=15+3
x=18
3\(\times\)(x-5)-16=11
3\(\times\)(x-5)=11+16
3\(\times\)(x-5)=27
x-5=27:3
x-5=9
x=9+5
x=14
Bài 2:
a, \(2^x-1=31\)
\(2^x=31-1\)
\(2^x=30\)
\(\Rightarrow\)Không có x thoả mãn điều kiện \(2^x=30\)
b, \(x^3-1=26\)
\(x^3=26+1\)
\(x^3=27\)
\(\Rightarrow x=3\) vì \(3^3=27\)
c, \(6^x-1+1=37\)
\(6^x-1=37-1\)
\(6^x-1=36\)
\(6^x=36+1\)
\(6^x=37\)
\(\Rightarrow\) Không có x thoả mãn điều kiện \(6^x=37\)
d, (x+2)\(^3\)-15\(^0\)=215
\(\left(x+2\right)^3-1=215\)
\(\left(x+2\right)^3=215+1\)
\(\left(x+2\right)^3=216\)
\(\left(x+2\right)^3=6^3\)
\(x+2=6\)
\(x=6-2\)
\(x=4\)
e, \(2\times\left(x-9\right)^2=2\)
\(\left(x-9\right)^2=2:2\)
\(\left(x-9\right)^2=1\)
\(\Rightarrow x-9=1\) vì \(1^2=1\)
x=1+9
x=10
g, \(3\times\left(x-5\right)^3=51\)
\(\left(x-5\right)^3=51:3\)
\(\left(x-5\right)^3=17\)
\(\Rightarrow\) Không có x thoả mãn điều kiện \(\left(x-5\right)^3=17\)
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Bài 1:
a)\(\left(x-2\right)-15=65\)
\(x-2=65+15\)
\(x-2=80\)
\(x=80+2\)
\(x=82\)
b)\(115-2\left(x-3\right)=35\)
\(2\left(x-3\right)=115-35\)
\(2\left(x-3\right)=80\)
\(x-3=80:2\)
\(x-3=40\)
\(x=40+3\)
c) \(35+2\left(x-3\right)=65\)
\(2\left(x-3\right)=65-35=30\)
\(x-3=30:2=15\)
\(x=15+3=18\)
d) \(3\left(x-5\right)-16=11\)
\(3\left(x-5\right)=11+16=27\)
\(x-5=27:3=9\)
\(x=9+5=14\)
Bài 2:
a) \(2^x-1=31\)
\(2^x=31+1=32\)
Vì \(2^5=32\Rightarrow x=5\)
b) \(x^3-1=26\)
\(x^3=26+1=27\)
Vì \(3^3=27\Rightarrow x=3\)
c)\(6^{x-1}+1=37\)
\(6^{x-1}=37-1=36\)
Vì \(6^6=36\Rightarrow x-1=6\Rightarrow x=6+1=7\)
d)\(\left(x+2\right)^3-15^0=215\)
\(\left(x+2\right)^3-1=215\)
\(\left(x+2\right)^3=215+1=216\)
Vì \(6^3=216\Rightarrow x+2=6\Rightarrow x=6-2=4\)
e)\(2\left(x-9\right)^2=2\)
\(\left(x-9\right)^2=2:2=1\)
Vì \(1^2=1\Rightarrow x-9=1\Rightarrow x=1+9=10\)
g) \(3\left(x-5\right)^3=51\)
\(\left(x-5\right)^3=51:3=17\)
Bài 1:
a)
\(\left(x-2\right)-15=65\)
\(x-2\) \(=65+15\)
\(x-2\) \(=\) \(80\)
\(x\) \(=80+2\)
\(x\) \(=82\)
b)
\(115-2\cdot\left(x-3\right)=35\)
\(2\cdot\left(x-3\right)=115-35\)
\(2\cdot\left(x-3\right)=80\)
\(x-3=80:2\)
\(x-3=40\)
\(x\) \(=40+3\)
\(x\) \(=43\)
c)
\(35+2\cdot\left(x-3\right)=65\)
\(2\cdot\left(x-3\right)=65-35\)
\(2\cdot\left(x-3\right)=30\)
\(x-3=30:2\)
\(x-3=15\)
\(x\) \(=15+3\)
\(x\) \(=18\)
d)
\(3\cdot\left(x-5\right)-16=11\)
\(3\cdot\left(x-5\right)\) \(=11+16\)
\(3\cdot\left(x-5\right)\) \(=27\)
\(x-5\) \(=27:3\)
\(x-5\) \(=9\)
\(x\) \(=9+5\)
\(x\) \(=14\)
Bài 2
a)
\(2^x-1=31\)
\(2^x\) \(=31+1\)
\(2^x\) \(=32\)
\(2^x\) \(=2^5\)
⇒ \(x=5\)
b)
\(x^3-1=26\)
\(x^3\) \(=26+1\)
\(x^3\) \(=27\)
\(x^3\) \(=3^3\)
⇒ \(x=3\)
c)
\(6^{x-1}+1=37\)
\(6^{x-1}\) \(=37-1\)
\(6^{x-1}\) \(=36\)
\(6^{x-1}\) \(=6^2\)
➞ \(x-1=2\)
\(x\) \(=2+1\)
\(x\) \(=3\)
d)
\(\left(x+2\right)^3-15^0=215\)
\(\left(x+2\right)^3-1=215\)
\(\left(x+2\right)^3=215+1\)
\(\left(x+2\right)^3=216\)
\(\left(x+2\right)^3=6^3\)
➞ \(x+2=6\)
\(x=6-2\)
\(x=4\)
e)
\(2\cdot\left(x-9\right)^2=2\)
\(\left(x-9\right)^2=2:2\)
\(\left(x-9\right)^2=1\)
\(\left(x-9\right)^2=1^2\)
➞ \(x-9=1\)
\(x=9+1\)
\(x=10\)
g)
\(3\cdot\left(x-5\right)^3=51\)
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