f) 5^x+2 = 625

=> 5^x+2 = 5⁴

=> x + 2 = 4

=> x = 2

g) ( x - 1 )^x+2 = ( x - 1 )^{x + 4}

=> ( x - 1 )^x+2 - ( x - 1 )^{x + 4} = 0

=> ( x - 1 )² [ 1 - ( x - 1 )² ] = 0

\(\Rightarrow\orbr{\begin{cases}\text{( x - 1 )}^2=\text{0}\\\text{1 - ( x - 1 )}^2=\text{0}\end{cases}\Rightarrow\orbr{\begin{cases}\text{x - 1 = 0}\\\text{( x - 1 )}^2=\text{1 - 0 = 1}\end{cases}\Rightarrow}\orbr{\begin{cases}\text{x = 1}\\\text{x - 1 = 1}\end{cases}\Rightarrow}\orbr{\begin{cases}\text{x = 1}\\\text{x = 2}\end{cases}}}\)

\(\frac{a}{b+c}=\frac{b}{c+a}=\frac{c}{a+b}=\frac{a+b+c}{2\left(a+b+c\right)}=\frac{1}{2}.\)

\(\Rightarrow\frac{b+c}{a}=\frac{a+c}{b}=\frac{a+b}{c}=2\)

\(\Rightarrow A=\frac{b+c}{a}+\frac{a+c}{b}+\frac{a+b}{c}=2+2+2=6\)

GTTĐ của \(\frac{x-3}{4}\)>0

=> GTNN của A=3

\(\frac{\text{2}}{\text{8}}=\frac{\text{5}}{\text{20}}\)

\(\frac{\text{2}}{\text{5}}=\frac{\text{8}}{\text{20}}\)

\(\frac{\text{20}}{\text{5}}=\frac{\text{8}}{\text{2}}\)

\(\frac{\text{20}}{\text{8}}=\frac{\text{5}}{\text{2}}\)

\(\frac{5}{20}=\frac{2}{8}\) 

\(\frac{20}{5}=\frac{8}{2}\)

\(\frac{8}{20}=\frac{2}{5}\)

\(\frac{20}{8}=\frac{5}{2}\)

9x2+2+80:2+40:2+20:2+10:2+5:2+2,5+900

đấy là 9x^2 hay là 9 x 2

tính rút gọn biểu thức hay tính j 

3^-1 x 3ⁿ + 5 x 3^n-1 = 162

=> 3^n-1 + 5 x 3^n-1 = 162

=> ( 5 + 1 ) x 3^n-1 = 162

=> 6 x 3^n-1 = 162

=> 3^n-1 = 162 : 6 = 27

=> 3^n-1 = 3³

=> n - 1 = 3

=> n = 4

Vậy ...................

3−1.3n+5.3n−1=1623−1.3n+5.3n−1=162

⇒3n−1+5.3n−1=162⇒3n−1+5.3n−1=162

⇒3n−1(1+5)=162⇒3n−1(1+5)=162

⇒3n−1.6=162⇒3n−1.6=162

⇒3n−1=162:6=27⇒3n−1=162:6=27

⇒3n−1=33⇒3n−1=33

⇒n−1=3⇒n−1=3

⇒n=4

k nha 

Gạch :D

a/ Xét tg MNP có MN=MP => tg MNP cân tại M

\(\Rightarrow\widehat{MNP}=\widehat{MPN}\)

Xét tg MNA và tg MPA có

AN=PN; MN=MP

\(\widehat{MNP}=\widehat{MPN}\)

\(\Rightarrow\Delta MNA=\Delta MPA\left(c.g.c\right)\)

b/

\(\Delta MNA=\Delta MPA\Rightarrow\widehat{MAN}=\widehat{MAP}\)

c/

\(\Delta MNA=\Delta MPA\Rightarrow\widehat{AMN}=\widehat{AMP}\) => MA là phân giác của \(\widehat{NMP}\)