Question

[Quyết Nguyễn]

hộ mik cột b đc ko 

Answer 1

[Nguyễn Lê Phước Thịnh]

b: (1/2)^x=1/32

=>(1/2)^x=(1/2)^5

=>x=5

b: (7/5)^x=343/125

=>(7/5)^x=(7/5)^3

=>x=3

b: (-3/2)^x=9/4

=>(-3/2)^x=(-3/2)^2

=>x=2

b: (-2/3)^x=-8/27

=>(-2/3)^x=(-2/3)^3

=>x=3

b: (3/5)^x+98/125=1

=>(3/5)^x=27/125

=>(3/5)^x=(3/5)^3

=>x=3

Answer 2

[HT.Phong (9A5)]

b1) \(\left(\dfrac{1}{2}\right)^x=\dfrac{1}{32}\)

\(\Rightarrow\left(\dfrac{1}{2}\right)^x=\left(\dfrac{1}{2}\right)^5\)

\(\Rightarrow x=5\)

b2) \(\dfrac{343}{125}=\left(\dfrac{7}{5}\right)^x\)

\(\Rightarrow\left(\dfrac{7}{5}\right)^3=\left(\dfrac{7}{5}\right)^x\)

\(\Rightarrow x=3\)

b3) \(\left(-\dfrac{3}{2}\right)^x=\dfrac{9}{4}\)

\(\Rightarrow\left(-\dfrac{3}{2}\right)^x=\left(-\dfrac{3}{2}\right)^2\)

\(\Rightarrow x=2\)

b4) \(\left(-\dfrac{2}{3}\right)^x=-\dfrac{8}{27}\)

\(\Rightarrow\left(-\dfrac{2}{3}\right)^x=\left(-\dfrac{2}{3}\right)^3\)

\(\Rightarrow x=3\)

b5) \(\left(\dfrac{3}{5}\right)^x+\dfrac{98}{125}=1\)

\(\Rightarrow\left(\dfrac{3}{5}\right)^x=1-\dfrac{98}{125}\)

\(\Rightarrow\left(\dfrac{3}{5}\right)^x=\dfrac{27}{125}\)

\(\Rightarrow\left(\dfrac{3}{5}\right)^x=\left(\dfrac{3}{5}\right)^3\)

\(\Rightarrow x=3\)