100 + 400 + 500 + 1000 = 2000

123 x 123 + 123 = 15252

(x + 3x) : 2 = 0,75

4x = 0.75 . 2 

4x = 1,5

x = 1,5 : 4

x = 0,375

(x+3x):2=0,75

=>4x=0,75 x2

=>4x=1,5

=>x=1,5:4

=>x=0,375

tíc mình nha

hthtehyzhzh

=400 nha bn

k mk nha

=40000

\(A=\frac{3}{2}\times\left(\frac{2}{1\times3}+\frac{2}{3\times5}+....+\frac{2}{44\times51}\right)\)

\(A=\frac{3}{2}\times\left(\frac{1}{1}-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+...+\frac{1}{44}-\frac{1}{51}\right)\)

\(A=\frac{3}{2}\times\left(1-\frac{1}{51}\right)\)

\(A=\frac{3}{2}\times\frac{50}{51}\)

\(A=\frac{25}{17}\)

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