Em đăng kí nhận quà của ô cửa thần kỳ.

Em đăng kí nhận gp ạ.

Em đăng kí nhận quà của ô cửa thần kỳ.

\(80\%=\dfrac{80}{100}=\dfrac{4}{5}\)

a) \(1^3+2^3=1+8=9\)

b) \(1^3+2^3+3^3=1+8+27=36\)

c) \(1^3+2^3+3^3+4^3=1+8+27+64=100\)

d) \(\left(2^{13}+2^5\right):\left(2^{10}+2^2\right)=2^3.\left(2^{10}+2^2\right):\left(2^{10}+2^2\right)=2^3=8\)

\(#NqHahh\)

Sửa câu g):

\(x^6:x^3=125\)

\(x^3=125=5^3\)

\(=>x=5\)

\(a\)) \(2^x=16\)

\(2^x=2^4\)

\(=>x=4\)

b) \(4^x=64\)

\(4^x=4^3\)

\(=>x=3\)

c) \(15^x=225\)

\(15^x=15^2\)

\(=>x=2\)

d) \(3^x.3=243\)

\(3^x=243:3\)

\(3^x=81=3^4\)

\(=>x=4\)

e) \(2^x.7=56\)

\(2^x=56:7\)

\(2^x=8=2^3\)

\(=>x=3\)

g) \(x^6:x^3=125\)

\(x^3=125=5^3\)

\(=>x=5\) hoặc \(x=-5\)

\(#NqHahh\)

\(B=\dfrac{1}{25.27}+\dfrac{1}{27.29}+\dfrac{1}{29.31}+...+\dfrac{1}{93.95}\)

\(B=\dfrac{1}{2}.\left(\dfrac{1}{25}-\dfrac{1}{27}+\dfrac{1}{27}-\dfrac{1}{29}+\dfrac{1}{29}-\dfrac{1}{31}+...+\dfrac{1}{93}-\dfrac{1}{95}\right)\)

\(B=\dfrac{1}{2}.\left(\dfrac{1}{25}-\dfrac{1}{95}\right)\)

\(B=\dfrac{1}{2}.\dfrac{14}{475}\)

\(B=\dfrac{7}{475}\)

\(#NqHahh\)

\(S=1+3+3^2+3^3+...+3^{100}\)

\(3S=3+3^2+3^3+3^4+...+3^{101}\)

\(3S-S=\left(3+3^2+3^3+3^4+...3^{101}\right)-\left(1+3+3^2+3^3+...+3^{100}\right)\)

\(2S=3^{101}-1\)

\(S=\dfrac{3^{101}-1}{2}\)

\(#NqHahh\)

2(x - 51) = 36

x - 51 = 36 : 2

x - 51 = 18

x = 18 + 51

x = 69