1,tìm x 2.3 mũ x=162 2 mũ x – 15=17 (7 mũx -11)mũ 3 = 5 mũ 2+200 x mũ 10=x

Question

1,tìm x
2.3 mũ x=162
2 mũ x – 15=17
(7 mũx -11)mũ 3 = 5 mũ 2+200
x mũ 10=x

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1 year 2020-11-14T04:05:46+00:00 2 Answers 113 views 0

1. Giải thích các bước giải:

2.3 ^ x=162
=>3^x=162:2
=>3^x=81
=>3^x=3^4
=>x=4
2 ^ x – 15=17
=>2^x=17+15
=>2^x=32
=>2^x=2^5
=>x=5
(7.x-11)^3=5^2. 2^5+200
=>(7.x – 11)^3=25 . 32+200
=>(7.x – 11)^3=800+200
=>(7.x – 11)^3=1000
=>(7.x – 11)^3=10^3
=>7.x – 11=10
=>7.x = 10+11
=>7.x=21
=>x=21:7
=>x=3

x^10=x
=>x^10-x=0
=>x^9 . x-x.1=0
=>x.(x^9 -1)=0
=>$$\left[ \begin{array}{l}x=0\\x^9 – 1=0\end{array} \right.$$
=>$$\left[ \begin{array}{l}x=0\\x^9=0+1\end{array} \right.$$
=>$$\left[ \begin{array}{l}x=0\\x^9=1\end{array} \right.$$
=>$$\left[ \begin{array}{l}x=0\\x^9=1^9\end{array} \right.$$
=>$$\left[ \begin{array}{l}x=0\\x=1\end{array} \right.$$

2. a) 3^x=162

2.3∧X=2.3∧4

⇒x=4

b)2∧x -15=17

2∧x=32

2∧X=2∧5

⇒x=5

(7x-11)∧3=5∧2+200

(7x-11)∧3=25.32+200

(7x-11)∧3=1000

(7x-11)∧3=10∧3

7x-11=10

7x=21

x=3

x∧10=x

⇒x∧10-x=0

⇒x.(x∧9-1)=0

TH1:⇒x=0

TH2:⇒x∧9-1=0⇒x=1

Vậy x=0 hoặc x=1