A) = 10 + ( - 29) = 19

B) = - 520- 1014 = - 494

D)= 350+ 9 * - 30 = 359 * -30 = -9770

tich mik mik tich lai cho!

1945

a) \(3^x-27.3^5.3^2=0\)

\(3^x-3^3.3^5.3^3=0\)

\(3^x=3^{13}\)

\(x=13\)

b) \(\left(-5+3x\right):4=16\)

\(-5+3x=64\)

\(3x=69\)

\(x=23\)

     \(\frac{x-29}{1970}+\frac{x-27}{1972}+\frac{x-25}{1974}+\frac{x-23}{1976}+\frac{x-1970}{29}+\frac{x-1972}{27}-6=0\)

\(\Leftrightarrow\)\(\frac{x-29}{1970}-1+\frac{x-27}{1972}-1+\frac{x-25}{1974}-1+\frac{x-23}{1976}-1+\frac{x-1970}{29}-1+\frac{x-1972}{27}-1=0\) \(\Leftrightarrow\) \(\frac{x-1999}{1970}+\frac{x-1999}{1972}+\frac{x-1999}{1974}+\frac{x-1999}{1976}+\frac{x-1970}{29}+\frac{x-1999}{27}=0\)

\(\Leftrightarrow\)\(\left(x-1999\right)\left(\frac{1}{1970}+\frac{1}{1972}+\frac{1}{1974}+\frac{1}{1976}+\frac{1}{29}+\frac{1}{27}\right)=0\)

Vì   \(\frac{1}{1970}+\frac{1}{1972}+\frac{1}{1974}+\frac{1}{1976}+\frac{1}{29}+\frac{1}{27}\ne0\)

\(\Rightarrow\)\(x-1999=0\)

\(\Leftrightarrow\)\(x=1999\)

Vậy...

Cảm ơn bạn nhiều nha. Lần sau mình có bài j khó nữa nhớ giúp mình vs nhá😊😊😊

3.5²-27:3² +5².4-18:3²

=3 . 25 - 27 : 9 + 25. 4 - 18 : 9

=75 - 3 + 100 - 2

=(75 - 3) + (100 - 2)

=72 + 98

=170

=3.25-27:9+25.4-18:9

=75-3+100-2

=72+100-2

=170

    \(3.5^2-27:3^2+5^2.4-18:3^2\)

\(=5^2\left(3+4\right)-\left(27+18\right):3^2\)

\(=25.7-45:9\)

\(=175-5\)

\(=170\)

Ta sẽ so sánh : 32²⁷ và 18³⁹

Có 18³⁹>16³⁹=(2⁴)³⁹=2¹⁵⁶

Lại có 32²⁷=(2⁵)²⁷=2¹³⁵

Vì 2¹³⁵<2¹⁵⁶ nên 32²⁷<18³⁹

=> -32²⁷>-18³⁹

32²⁷ = 2^{5 x 27} = 2¹³⁵

18³⁹ > 16³⁹ = 2^{4 x 39} = 2¹⁵⁶

mà 2¹³⁵ < 2¹⁵⁶

=> -2¹³⁵ > -2¹⁵⁶ 

=> -32²⁷ > -18³⁹