`(-3 .7^4 + 7^3)/(7^5 .6 -7^3 .2)`

`=(7^3 .(-3.7 +1))/(7^3 (7^2 .6 -2))`

`=(-20)/292=-5/73`

Giải:

\(\dfrac{-3.7^4+7^3}{7^5.6-7^3.2}\) 

\(=\dfrac{-3.7.7^3+7^3}{7^3.7^2.6-7^3.2}\) 

\(=\dfrac{7^3.\left(-3.7+1\right)}{7^3.\left(7^2.6-2\right)}\) 

\(=\dfrac{-21+1}{49.6-2}\) 

\(=\dfrac{-20}{294-2}\) 

\(=\dfrac{-20}{292}=\dfrac{-5}{73}\)

x.(53+42+5)=4.75

x.100=4.75

x=4.75x100

x=475

cam on

\(x.\left(53+42+5\right)=4.75\)

\(x.100=4.75\)

\(x=4.75.100\)

\(x=475\)

3,75 + 1,25*X=4*75

=>3,75+1,25*X=300

=>1,25 * X =300 - 3,75=296,25

=> X = 296,25 / 1,25 = 237

TICK NHA

a) \(243^5=\left(3^5\right)^5=3^{25}\)

\(3\cdot27^5=3\cdot\left(3^3\right)^5=3\cdot3^{15}=3^{16}\)

mà \(3^{25}>3^{16}\)

nên \(243^5>3\cdot27^5\)

b) \(625^5=\left(5^4\right)^5=5^{20}\)

\(125^7=\left(5^3\right)^7=5^{21}\)

mà \(5^{20}< 5^{21}\)

nên \(625^5< 125^7\)

c) \(202^{303}=\left(202^3\right)^{101}=8242408^{101}\)

\(303^{202}=\left(303^2\right)^{101}=91809^{101}\)

mà \(8242408^{101}>91809^{101}\)

nên \(202^{303}>303^{202}\)

47x + 52x + x = 4.75 = 300

x . ( 47 + 52 + 1 ) = 300

x . 100 = 300

x = 300 : 100

x = 3

47x + 52x + x = 4.75

=> 100x = 300

x = 3          

(115x+3⁴)7³=4.7⁵

=>(115x+81).343=4.16807

=>(115x+81).343=67228

=>(115x+81)=67228:343

=>115x+81=196

=>115x=196-81

=>115x=115

=>x=115:115

=>x=1

Vậy x=1

=(115* x +81)*343=67228

=>(115* x+81)=67228:343=196

=>115*x=196-81=115

=>x=115/115=1

Vậy x=1