Question

Bài 1

a) [ ( 8.x - 12 ) : 4 ] . 3³ = 3 ⁶

b) 3²⁺¹ + 3^x = 36

c) 2^{x+1 =16}

Answer 1

a) Ta có: \(\left[\frac{\left(8x-12\right)}{4}\right]\cdot3^3=3^6\)

\(\Leftrightarrow\frac{8x-12}{4}=3^3\)

\(\Leftrightarrow2x-3=3^3\)

\(\Leftrightarrow2x-3=27\)

\(\Leftrightarrow2x=30\)

hay x=15

Vậy: x=15

b) Ta có: \(3^{2+1}+3^x=36\)

\(\Leftrightarrow3^3+3^x=36\)

\(\Leftrightarrow3^x=9\)

hay x=2

Vậy: x=2

c) Ta có: \(2^{x+1}=16\)

\(\Leftrightarrow2^{x+1}=2^4\)

\(\Leftrightarrow x+1=4\)

hay x=3

Vậy: x=3

Answer 2

1.a)

[(8x - 12) : 4] . 3³ = 3⁶

(8x - 12) : 4 = 3⁶ : 3³ = 3³ = 27

8x - 12 = 27 . 4 = 108

8x = 108 + 12 = 120

x = 120 : 8 = 15

b)

3²⁺¹ + 3^x = 36

27 + 3^x = 36

3^x = 36 - 27 = 9 = 3²

=> x = 2

Answer 3

1.c) (cho hỏi câu c chỗ =16 bạn viết nhầm phải hông?)

C1: 2^{x+1 = 16}

2^{x = 16 - 1 = 15}

C2: 2^x+1 = 16

2^x+1 = 2⁴

=> x + 1 = 4

x = 4 - 1 = 3