B

b. 24 650 : 120 = 205 (dư 50)

B

B

B

Có 3 góc tù

100+650=750

duyet nha

x + 650 = 5000

x          = 5000-650

x          = 4530

x + 650 = 50 x 100

x + 650 = 5000

x          = 5000 - 650

x          = 4350

\(x+650=50\times100\)

\(\Leftrightarrow x+650=5000\)

\(\Leftrightarrow x=5000-650\)

\(\Leftrightarrow x=4350\)

x +100 = 500 : 2

x+ 100 = 250

x=250-100

x= 150

x+500= 650

x= 650-500 

x= 150 

k giúp mik nhé

x + 100 = 500 : 2

x + 100 = 250

x = 250 - 100

x = 150

x + 500 = 600

x = 600 - 500

x = 100

K mk mk k lại

Hứa luôn 

150 HẾT

a: \(\dfrac{x^3}{8}=\dfrac{y^3}{64}=\dfrac{z^3}{216}\)

=>\(\left(\dfrac{x}{2}\right)^3=\left(\dfrac{y}{4}\right)^3=\left(\dfrac{z}{6}\right)^3\)

=>\(\dfrac{x}{2}=\dfrac{y}{4}=\dfrac{z}{6}\)

=>\(\dfrac{x}{1}=\dfrac{y}{2}=\dfrac{z}{3}\)

Đặt \(\dfrac{x}{1}=\dfrac{y}{2}=\dfrac{z}{3}=k\)

=>x=k; y=2k; z=3k

\(x^2+y^2+z^2=14\)

=>\(k^2+4k^2+9k^2=14\)

=>\(14k^2=14\)

=>\(k^2=1\)

=>k=1 hoặc k=-1

TH1: k=1

=>\(x=k=1;y=2k=2\cdot1=2;z=3k=3\cdot1=3\)

TH2: k=-1

=>\(x=k=-1;y=2k=2\cdot\left(-1\right)=-2;z=3k=3\cdot\left(-1\right)=-3\)

b: \(\dfrac{x^3}{8}=\dfrac{y^3}{27}=\dfrac{z^3}{64}\)

=>\(\left(\dfrac{x}{2}\right)^3=\left(\dfrac{y}{3}\right)^3=\left(\dfrac{z}{4}\right)^3\)

=>\(\dfrac{x}{2}=\dfrac{y}{3}=\dfrac{z}{4}\)

Đặt \(\dfrac{x}{2}=\dfrac{y}{3}=\dfrac{z}{4}=k\)

=>x=2k; y=3k; z=4k

\(x^2+2y^2-3z^2=-650\)

=>\(\left(2k\right)^2+2\cdot\left(3k\right)^2-3\cdot\left(4k\right)^2=-650\)

=>\(4k^2+18k^2-3\cdot16k^2=-650\)

=>\(-26\cdot k^2=-650\)

=>\(k^2=25\)

=>\(\left[{}\begin{matrix}k=5\\k=-5\end{matrix}\right.\)

TH1: k=5

=>\(x=2\cdot5=10;y=3\cdot5=15;z=4\cdot5=20\)

TH2: k=-5

=>\(x=2\cdot\left(-5\right)=-10;y=3\cdot\left(-5\right)=-15;z=4\cdot\left(-5\right)=-20\)

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

\(=3^x\left(3^1+3^2+3^3+3^4\right)+...+3^{x+96}\left(3^1+3^2+3^3+3^4\right)=3^x.120+3^{x+4}.120+...+3^{x+96}.120=120\left(3^x+3^{x+4}+...+3^{x+96}\right)⋮120\)