\(4x^2+4x+1=\left(x-2\right)^2\\ \Leftrightarrow\left(2x+1\right)^2=\left(x-2\right)^2\\ \Leftrightarrow\left[{}\begin{matrix}2x+1=x-2\\2x+1=2-x\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-3\\x=\dfrac{1}{3}\end{matrix}\right.\)

Để (2n+14) ⋮ (2n+1) thì (2n+1) + 13 ⋮ (2n+1) 

Suy ra 2n+1 ∈ Ư(13)

\(\Rightarrow2n+1\in\left\{\pm1;\pm13\right\}\\ \Rightarrow n\in\left\{0;-1;-7;6\right\}\)

a) x = \(\dfrac{24}{-54}\) = \(\dfrac{-4}{9}\) = \(\dfrac{-20}{45}\)

y = \(\dfrac{-33}{55}\) = \(\dfrac{-3}{5}\) = \(\dfrac{-27}{45}\)

Vì \(\dfrac{-20}{45}\) > \(\dfrac{-27}{45}\) ⇒ \(\dfrac{24}{-54}\) > \(\dfrac{-33}{55}\) ⇒ x > y 

b) x = \(\dfrac{-19}{23}\) = \(\dfrac{4}{23}\) - 1

y = \(\dfrac{-25}{29}\) = \(\dfrac{4}{29}\) - 1

Vì \(\dfrac{4}{23}\) > \(\dfrac{4}{29}\) ⇒ \(\dfrac{4}{23}\) - 1 > \(\dfrac{4}{29}\) - 1 ⇒ \(\dfrac{-19}{23}\) > \(\dfrac{-25}{29}\) ⇒ x > y

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

\(\dfrac{\overline{ab}}{\overline{bc}}=\dfrac{a}{c}\Rightarrow\dfrac{10a+b}{10b+c}=\dfrac{a}{c}=\dfrac{9a+b}{10b}\\ =\dfrac{111...11\left(9a+b\right)}{111...11.10b}\)(có n chữ số 1 trong 111...11)

\(\dfrac{999...99a+111...11b}{111.110b}\\ =\dfrac{999...99a+a+111...11}{111.10b+c}=\dfrac{abbb...bb}{bbb...bc}=\dfrac{a}{c}\)(đpcm)

6 x ( X + 9845 ) = 29042 x 6

X + 9845 = 29042

X = 29042 - 9845

X = 19197.

6 \(\times\) (\(x\) + 9845) = 29042 \(\times\) 6

       (\(x\) + 9845) = 29042 \(\times\)6 : 6

        \(x\) + 9845 = 29042

        \(x\)             = 29042 - 9845

        \(x\)             = 19197

\(1,\left(x-3\right)^2+3-x=0\)

\(\Leftrightarrow x^2-6x+9+3-x=0\)

\(\Leftrightarrow x^2-7x+12=0\)

\(\Leftrightarrow x^2-3x-4x+12=0\)

\(\Leftrightarrow\left(x-3\right)\left(x-4\right)=0\)

\(\Leftrightarrow\left\{{}\begin{matrix}x-3=0\\x-4=0\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=3\\x=4\end{matrix}\right.\)

Vậy.........

\(\left(x-3\right)^2+3-x=0\\ \Leftrightarrow x^2-6x+9+3-x=0\\ \Leftrightarrow x^2-7x+12=0\\ \Leftrightarrow x^2-3x-4x+12=0\\ \Leftrightarrow x\left(x-3\right)-4\left(x-3\right)=0\\ \Leftrightarrow\left(x-3\right)\left(x-4\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x-3=0\\x-4=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=3\\x=4\end{matrix}\right.\)

Vậy \(S=\left\{3;4\right\}\)

1,-(4+7)=(-4-7)

2,-(12-25)=(-12+25)

3,-(-8+7)=(8-7)

4,+(-15-4)=(-15-4)

5,+(23-12)=(23-12).

bằng nhau hết nha bạn

30874 + 14563 = 45437.

45437

Tổng diện tích hình vuông A,C,D :

\(5.5+2.2+3.3=40\left(cm^2\right)\)

mà tấm bìa cũng là hình vuông

Nên diện tích của hình vuông B là 

\(49-40=9\left(cm^2\right)\)

Diện tích hình vuông A gấp \(\dfrac{25}{9}\) lần hình vuông B