Question

bài 1 tìm x

a\(\left(3x-15\right)=3^7\div3^5\)

b\(\left(4x+32\right)=43\times2^2\)

c \(6^{2x-7}=216\)

d \(5^x+5^{x+2}=650\)

e\(\left(3x-7\right)^4=81\)

bài 2 tính a ,b,c, biết

a, \(a+b=12,b+c=18,c+a=-4\)

b,\(a\times b=\dfrac{5}{6},b\times c=\dfrac{6}{7},c\times a=\dfrac{5}{7}\)

c,\(2a-3b+4c=24\)và\(1a=\dfrac{3}{4}b=\dfrac{1}{3}c\)

giúp mình nhé mình đang cần gấp

Answer 1

Câu 1:

a: \(\left(3x-15\right)=3^7:3^5\)

=>3x-15=9

=>3x=24

hay x=8

b: \(\left(4x+32\right)=43\cdot2^2\)

=>4x+32=172

=>4x=140

hay x=35

c: \(6^{2x-7}=216\)

=>2x-7=3

=>2x=10

hay x=5

d: \(5^x+5^{x+2}=650\)

\(\Leftrightarrow5^x\cdot26=650\)

\(\Leftrightarrow5^x=25\)

hay x=2