x:0,25+x+x:0,2=120

x*4+x*1+x*5=120

x*(4+1+5)=120

x*10=120

x=120:10

x=10

*=nhân 

thanhs linh

x=8.541666667

120% =1,2 

1,2 . x - 0,25=10

1,2 . x= 10+ 0,25

1,2 .x =10,25

       x= 10,25 : 1,2

       x=8,5416........

\(4^x=32^{10}\)

\(\Rightarrow4^x=4^{80}\)

\(\Rightarrow x=80\)

\(4^x=32^{10}\)

\(\Rightarrow2^{2x}=2^{50}\)

\(\Rightarrow2x=50\Rightarrow x=25\)

\(2\left(x-1\right)-5\left(x+2\right)=-10\\ \Rightarrow2x-2-5x-10=-10\\ \Rightarrow-3x=2\\ \Rightarrow x=\dfrac{-2}{3}\)

Vậy \(x=\dfrac{-2}{3}\)

x:2=y:3->x/2=y/3

Áp dụng tính chất dãy tỉ số bằng nhau,ta có:

x/2=y/3=x+y/2+3=10/5=2

từ: x/2=2->x=2.2=4

y/3=2->y=2.3=6

vậy...

\(\dfrac{x}{2}=\dfrac{y}{3}\Rightarrow\dfrac{x}{2}=\dfrac{y}{3}=\dfrac{x+y}{2+3}=\dfrac{10}{5}=2\) (theo tính chất củadãy tỉ số bằng nhau)

\(\Rightarrow x=4,y=6\)

-14 -x =-25

x=-14-(-25)

x=11

(-14)-x=(-10)-(-15)

(-14)-x=5

x=-14-5

x=-19

Ta có: \(2-y=10\Rightarrow y=-8\)

Ta có: \(\dfrac{x}{3}=\dfrac{y}{-2}\Rightarrow x=\dfrac{y.3}{-2}=\dfrac{\left(-8\right).3}{-2}=12\)

\(\left(2x-1\right)^2=81\\ \Rightarrow\left(2x-1\right)=\sqrt{81}=9\\ \Rightarrow2x=9+1=10\\ \Rightarrow x=\dfrac{10}{2}=5\)

\(2^3.5-\left(x+3^2\right)=10\\ \Rightarrow8.5-\left(x+9\right)=10\\ \Rightarrow x+9=8.5-10=40-10=30\\ \Rightarrow x=30-9=21\)

\(P=\dfrac{4}{5}\left(x+y\right)+\left(\dfrac{6x}{5}+\dfrac{30}{x}\right)+\left(\dfrac{y}{5}+\dfrac{5}{y}\right)\ge\dfrac{4}{5}.10+2\sqrt{\dfrac{180x}{5x}}+2\sqrt{\dfrac{5y}{5y}}=22\)

\(P_{min}=22\) khi \(x=y=5\)