15 gio nha ban!

Câu 2:

\(a,=2x\left(x^2-4x+4\right)=2x\left(x-2\right)^2\\ b,=2x\left(y+1\right)+z\left(y+1\right)=\left(2x+z\right)\left(y+1\right)\\ c,=\left(x+1\right)^2-y^2=\left(x+y+1\right)\left(x-y+1\right)\)

Câu 3:

\(a,\Leftrightarrow x^2-36-x^2-6x-9=9\\ \Leftrightarrow-6x=54\Leftrightarrow x=-9\\ b,\Leftrightarrow\left(2x-1-5x+5\right)\left(2x-1+5x-5\right)=0\\ \Leftrightarrow\left(4-3x\right)\left(7x-6\right)=0\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{4}{3}\\x=\dfrac{6}{7}\end{matrix}\right.\)

60km/h:v

hinhf như là 60km/h

60km/h

a) 72,5 x 4 + 5 x 72,5 + 72,5

= 72,5 x 4 + 5 x 72,5 + 72,5 x 1

= 72,5 x (4 + 5 + 1)

= 72,5 x 10

= 725

b) 49,23 + 35,48 + 50,77 + 64,52

= (49,23 + 50,77) + (35,48 + 64,52)

= 100 + 100

= 200

bây giờ là 4 giờ

đây là bài giải trên violympic lớp 5. 

k mik nha .

cảm ơn

THANK YOU VINAMIU

là 8 giờ

(3x - 1)³ = 125

(3x -1)³ = 5³

3x - 1 = 5

3x = 5 + 1 

3x = 6

x = 6 : 3

x = 2

Ta có: \(\left(5+\dfrac{3}{16}-\dfrac{2}{5}\right):\dfrac{-6}{7}-\left(\dfrac{3}{5}+1+\dfrac{3}{16}\right)\cdot\dfrac{-7}{6}\)

\(=\left(5+\dfrac{3}{16}-\dfrac{2}{5}-\dfrac{3}{5}-1-\dfrac{3}{16}\right)\cdot\dfrac{-7}{6}\)

\(=3\cdot\dfrac{-7}{6}=\dfrac{-7}{2}\)