48.14 + 26.28 + 400

= 48.14 + 26.2.14 + 400

= 14. (48 + 52) +400

=14.100 + 400

= 1400 + 400

=1800

48 x 14 + 26 x 28 + 400

= 48 x 14 + 26 x 2 x 14 + 400

= 48 x 14 + 52 x 14 + 400

= 14 x ( 48 + 52 ) + 400

= 14 x 100 + 400

= 1400 + 400

= 1800

\(=\dfrac{1}{2\cdot5}+\dfrac{1}{5\cdot8}+\dfrac{1}{8\cdot11}+...+\dfrac{1}{17\cdot20}\)

=1/3(3/2*5+3/5*8+...+3/17*20)

=1/3(1/2-1/5+1/5-1/8+...+1/17-1/20)

=1/3*9/20=3/20

= 250

Lấy mt ra

\(\left(-375\right)+625=250\)

250

làm hết =)?

Đặt E(x)=0

\(\Leftrightarrow2x^2-3x=0\)

\(\Leftrightarrow x\left(2x-3\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\2x-3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\2x=3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{3}{2}\end{matrix}\right.\)

Vậy: \(S=\left\{0;\dfrac{3}{2}\right\}\)

Đặt E(x)=0

S={0;32}

V=B.h (V là thể tích;B diện tích đáy;h là chiều cao)

cụ thể hơn mau

\(=962\cdot\dfrac{26}{100}=250,12\)

Bài 10:

a: \(A=\dfrac{10}{11}+\dfrac{1}{11}\cdot\dfrac{3}{11}+\dfrac{1}{11}\cdot\dfrac{8}{11}\)

\(=\dfrac{10}{11}+\dfrac{1}{11}\left(\dfrac{3}{11}+\dfrac{8}{11}\right)\)

\(=\dfrac{10}{11}+\dfrac{1}{11}=\dfrac{11}{11}=1\)

b: \(B=\dfrac{5}{7}\cdot\dfrac{40}{11}-\dfrac{5}{11}\cdot\dfrac{117}{7}\)

\(=\dfrac{5}{7}\left(\dfrac{40}{11}-\dfrac{117}{11}\right)\)

\(=\dfrac{5}{7}\cdot\dfrac{-77}{11}=\dfrac{5}{7}\cdot\left(-7\right)=-5\)

c: \(C=\dfrac{3}{7}\cdot\dfrac{9}{11}+\dfrac{3}{7}\cdot\dfrac{5}{11}-\dfrac{3}{7}\cdot\dfrac{25}{11}\)

\(=\dfrac{3}{7}\left(\dfrac{9}{11}+\dfrac{5}{11}-\dfrac{25}{11}\right)\)

\(=\dfrac{3}{7}\cdot\dfrac{-11}{11}=-\dfrac{3}{7}\)

d: \(D=\dfrac{5}{7}\cdot\dfrac{-3}{38}\cdot\dfrac{7}{10}\cdot\dfrac{19}{6}\)

\(=\dfrac{5}{7}\cdot\dfrac{7}{10}\cdot\dfrac{-3}{6}\cdot\dfrac{19}{38}\)

\(=\dfrac{5}{10}\cdot\dfrac{-1}{2}\cdot\dfrac{1}{2}=\dfrac{-1}{8}\)

Bài 11:

a: Sau hai ngày thì lượng sữa còn lại chiếm:

\(1-\dfrac{1}{5}-\dfrac{1}{4}=1-\dfrac{9}{20}=\dfrac{11}{20}\)(hộp)

b: Lượng sữa còn lại sau 2 ngày là:

\(1000\cdot\dfrac{11}{20}=550\left(ml\right)\)

\(936-\left(4x+5x\right)=900\\ 936-9x=900\\ 9x=36\\ x=4\)