Question

[Pham Thu Trang]

a. 7. 3 mũ x=5.3 mũ 7+2.3 mũ7

b. 4 mũ x+3 -3.4 mũ x+1=13.4 mũ 11

c. (x+1) mũ 2+|x+2|=0

d. (x-1) mũ 13=(x-1) mũ 12

Giúp mk với

Answer 1

[Nguyễn Lê Phước Thịnh]

a: \(7\cdot3^x=5\cdot3^7+2\cdot3^7\)

\(\Leftrightarrow7\cdot3^x=7\cdot3^7\)

=>3^x=3⁷

hay x=7

b: \(4^{x+3}-3\cdot4^{x+1}=13\cdot4^{11}\)

\(\Leftrightarrow4^{x+1}\left(4^2-3\right)=13\cdot4^{11}\)

=>x+1=11

hay x=10

d: \(\left(x-1\right)^{13}=\left(x-1\right)^{12}\)

\(\Leftrightarrow\left(x-1\right)^{12}\left(x-2\right)=0\)

hay \(x\in\left\{1;2\right\}\)