CHTT

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Số tiền lãi là:

720 000 - 600 000 = 120 000 (đồng)

Tỉ số phần trăm giữa tiền lãi và tiền vốn là:

(120 000 : 600 000) X100 = 20%

Đ/s:...

90% của 2000 là:2000;100x90=1800

Ta có: \(\left(4x-1\right)^2=\left(1-4x\right)^4\)

Đặt \(\left(4x-1\right)^2=t\) \(\left(t\ge0\right)\)

\(\Rightarrow1-4x=-t\)

\(\Leftrightarrow t=-t^2\)

\(\Leftrightarrow t^2+t=0\)

\(\Leftrightarrow\left[{}\begin{matrix}t=0\\t=-1\left(\text{loại}\right)\end{matrix}\right.\)

Ta có: \(t=0\)

\(\Leftrightarrow(4x-1)^2 =0\)

\(\Leftrightarrow4x-1=0\)

\(\Rightarrow x=\dfrac{1}{4}\)

hình như là thứ sáu đó bn

a. \(m_{Fe_3O_4}=n_{Fe_3O_4}.M_{Fe_3O_4}=0,05.232=11,6\left(g\right)\)

b. \(n_{SO_2}=\dfrac{V_{SO_2}}{22,4}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)

\(m_{SO_2}=n_{SO_2}.M_{SO_2}=0,1.64=6,4\left(g\right)\)

c. \(m_{NaCl}=n_{NaCl}.M_{NaCl}=2.58,5=117\left(g\right)\)

d. \(n_{H_2}=\dfrac{V_{H_2}}{22,4}=\dfrac{5,6}{22,4}=0,25\left(mol\right)\)

\(m_{H_2}=n_{H_2}.M_{H_2}=0,25.2=0,5\left(g\right)\)

''hình'' dau ban

\(\dfrac{2x}{x-2}+\dfrac{3x}{x+2}-\dfrac{x\left(x+6\right)}{x^2-4}\)

\(=\dfrac{2x}{x-2}+\dfrac{3x}{x+2}-\dfrac{x\left(x+6\right)}{\left(x-2\right)\left(x+2\right)}\)

\(=\dfrac{2x\left(x+2\right)}{\left(x-2\right)\left(x+2\right)}+\dfrac{3x\left(x-2\right)}{\left(x-2\right)\left(x+2\right)}-\dfrac{x\left(x+6\right)}{\left(x-2\right)\left(x+2\right)}\)

\(=\dfrac{2x^2+4x+3x^2-6x-x^2-6x}{\left(x-2\right)\left(x+2\right)}\)

\(=\dfrac{4x^2-8x}{\left(x-2\right)\left(x+2\right)}\)

\(=\dfrac{4x\left(x-2\right)}{\left(x-2\right)\left(x+2\right)}\)

\(=\dfrac{4x}{x+2}\)