a) x = 16 24 b) 2 1 7 5 ( x = + ) ( ) c) ( ) 3 4. 5 7 101 x + = d) 1 2 .3 15 39. x+ + =

2 bình luận về “a) x = 16 24 b) 2 1 7 5 ( x = + ) ( ) c) ( ) 3 4. 5 7 101 x + = d) 1 2 .3 15 39. x+ + =”

1. a) x – 16 = 24

   x = 24 + 16

   x = 40 

   Vậy x = 40

   ———————

   b) 2(x – 1) = 7 + (-5)

   2(x – 1) = 2

   x – 1 = 2 : 2

   x – 1 = 1

   x = 1 + 1

   x = 2

   Vậy x = 2

   ———————–

   c)4 (x + 50)^3 – 7=101

   4(x + 50)^3 = 101 + 7

   4(x + 50)^3 = 108

   (x + 50)^3 = 108 : 4

   (x + 50)^3 = 27

   => (x + 50)^3 = (-3)^3 = 3^3

   TH1 : (x + 50)^3 = (-3)^3

   => x + 50 = -3

   x = -3 – 50

   x = -53

   TH2 : (x + 50)^3 = 3^3

   => x + 50 = 3

   x = 3 – 50

   x = -47

   Vậy x = -47 hoặc x = -53

   ———————————–

   d) 2^(x + 1) . 3 + 15 = 39

   2^(x + 1) . 3 = 39 – 15

   2^(x + 1) . 3 = 24

   2^(x + 1) = 24 : 3

   2^(x + 1) = 8

   => 2^(x + 1) = 2^3

   => x + 1 = 3

   => x = 3 – 1

   x = 2

   Vậy x = 2

   @Chris 

   Trả lời
2. $\text{a) x – 16 = 24}$

   $\text{⇔ x = 24 + 16 = 40}$

   $\text{Vậy: x = 40}$

   $\text{b) 2(x – 1) = 7 + (-5)}$

   $\text{⇔ 2x – 2 = 2}$

   $\text{⇔ 2x = 2 + 2 = 4}$

   $\text{⇔ x = 2}$

   $\text{Vậy: x = 2}$

   $\text{c) 4(x + 50)³ – 7 = 101}$

   $\text{⇔ 4(x + 50)³ = 101 + 7 = 108}$

   $\text{⇔ (x + 50)³ = 108/4 = 27}$

   $\text{⇔ x + 50 = 27 = 3}$

   $\text{⇔ x = 3 – 50 = -47}$

   $\text{Vậy: x = -47}$

   $\text{d) $2^{x+1}$ .3 + 15 = 39 }$

   $\text{⇔ $2^{x+1}$.3 = 39 – 15 = 24}$

   $\text{⇔ $2^{x+1}$ = 24/3 = 8}$

   $\text{⇔ $2^{x+1}$ = 2³}$

   $\text{⇔ x + 1 = 3}$

   $\text{⇔ x = 3 – 1 = 2}$

   $\text{Vậy: x = 2}$

   Trả lời