\(P=3^{10}+3^{11}+3^{12}\)

\(=3^{10}\cdot\left(1+3+3^2\right)\)

\(=3^{10}\cdot13\)

Vì \(13⋮13\) nên \(3^{10}\cdot13⋮13\)

hay \(P⋮13\)

Vậy ...

#\(Toru\)

P = 3¹⁰ + 3¹¹ + 3¹²

= 3¹⁰.(1 + 3 + 3²)

= 3¹⁰ . 13 ⋮ 13

Vậy P ⋮ 13

\(\dfrac{2x-3}{4}.\dfrac{6}{5}=\dfrac{21}{10}\\ \Leftrightarrow\dfrac{2x-3}{4}=\dfrac{7}{4}\\ \Leftrightarrow2x-3=7\\ \Leftrightarrow2x=10\\ \Leftrightarrow x=5\)

x = 5

x = 5

Đề yêu cầu gì vậy em? Rút gọn?

\(D=\dfrac{1}{3^2}+\dfrac{1}{3^4}+\dfrac{1}{3^6}+...+\dfrac{1}{3^{100}}\)

\(\Rightarrow9D=1+\dfrac{1}{3^2}+\dfrac{3}{3^4}+...+\dfrac{1}{3^{98}}\)

\(\Rightarrow9D-D=1-\dfrac{1}{3^{100}}\)

\(\Rightarrow8D=1-\dfrac{1}{3^{100}}\)

\(\Rightarrow D=\dfrac{1}{8}\left(1-\dfrac{1}{3^{100}}\right)\)

a) 3x(x-2)-x+2=0

⇔3x(x-2)-(x-2)=0

⇔(3x-1)(x-2)=0

⇔3x-1=0⇔x=1/3

⇔x-2=0⇔x=2

1T

2F

3C

4A

1Unless Tom studied hard, he wouldn't get good marks

2Tam had a stomachache because he ate a lot last night

\(-\dfrac{3}{5};0;\dfrac{1}{2};\dfrac{2}{3}\)

-3/5; 0; 1/2; 2/3

-3/5 ; 0 ; 1/2 ; 2/3

đồ đồ fa fa đồ fa mi fa

Fa(tính cả nốt trên);Son;Son;Son;Fa;Mi;Rê;Đồ