(-375)+625
giải chi tiết ra nhé
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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
⇔2x2−3x=0⇔2x2−3x=0
⇔x(2x−3)=0⇔x(2x−3)=0
⇔[x=02x−3=0⇔[x=02x=3⇔⎡⎣x=0x=32⇔[x=02x−3=0⇔[x=02x=3⇔[x=0x=32
Vậy: S={0;32}
V=B.h (V là thể tích;B diện tích đáy;h là chiều cao)
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:
\(1000\cdot\dfrac{11}{20}=550\left(ml\right)\)
\(936-\left(4x+5x\right)=900\\ 936-9x=900\\ 9x=36\\ x=4\)
\(d,\dfrac{5}{7}+\dfrac{9}{23}+-\dfrac{12}{7}+\dfrac{14}{23}\)
\(=\left(\dfrac{5}{7}+\dfrac{-12}{7}\right)+\left(\dfrac{9}{23}+\dfrac{14}{23}\right)\)
\(=-\dfrac{7}{7}+\dfrac{23}{23}\)
\(=\left(-1\right)+1=0\)
\(e,\dfrac{3}{17}+-\dfrac{5}{13}+-\dfrac{18}{35}+\dfrac{14}{17}+\dfrac{17}{-35}+-\dfrac{8}{13}\)
\(=\left(\dfrac{3}{17}+\dfrac{14}{17}\right)+\left(\dfrac{-5}{13}+\dfrac{-8}{13}\right)+\left(\dfrac{-18}{35}+\dfrac{-17}{35}\right)\)
\(=\dfrac{17}{17}+\dfrac{-13}{13}+-\dfrac{35}{35}\)
\(=1+\left(-1\right)+\left(-1\right)=0+\left(-1\right)=-1\)
\(f,\dfrac{-3}{8}. \dfrac{1}{6}+\dfrac{3}{-8}.\dfrac{5}{6}+\dfrac{-10}{16}\)
\(=\dfrac{-3}{8}.\dfrac{1}{6}+\dfrac{-3}{8}.\dfrac{5}{6}+\dfrac{-10}{16}\)
\(=\dfrac{-3}{8}.\left(\dfrac{1}{6}+\dfrac{5}{6}\right)+-\dfrac{10}{16}\)
=\(\dfrac{-3}{8}.1+\dfrac{-10}{16}\)
\(=\dfrac{-3}{8}+\dfrac{-10}{16}\)
\(=\dfrac{-6}{16}+\dfrac{-10}{16}=\dfrac{-16}{16}=-1\)
\(g,\dfrac{-4}{11}.\dfrac{5}{15}.\dfrac{11}{-4}=\dfrac{-4}{11}.\dfrac{5}{15}.\dfrac{-11}{4}\)
\(=\left(\dfrac{-4}{11}.\dfrac{-11}{4}\right).\dfrac{5}{15}\)
\(=1.\dfrac{5}{15}=1.\dfrac{1}{3}=\dfrac{1}{3}\)
\(h,\dfrac{7}{36}-\dfrac{8}{-9}+\dfrac{-2}{3}=\dfrac{7}{36}-\dfrac{-8}{9}+\dfrac{-2}{3}\)
\(=\dfrac{7}{36}-\dfrac{-32}{36}+\dfrac{-24}{36}=\dfrac{7-\left(-32\right)+\left(-24\right)}{36}\)
\(=\dfrac{15}{56}=\dfrac{5}{12}\)
Tick mình nha ^^
d.\(\dfrac{5}{7}\)+\(\dfrac{9}{23}\)+\(\dfrac{12}{7}\)+\(\dfrac{14}{23}\)=(\(\dfrac{5}{7}\)+\(\dfrac{12}{7}\))+(\(\dfrac{9}{23}\)+\(\dfrac{14}{23}\))
=\(\dfrac{17}{7}\)+ 1 = \(\dfrac{24}{7}\)
e.\(\dfrac{3}{17}\)+\(\dfrac{-5}{13}\)+\(\dfrac{-18}{35}\)+\(\dfrac{14}{17}\)+\(\dfrac{17}{-35}\)+\(\dfrac{-8}{13}\)
=(\(\dfrac{3}{17}\)+\(\dfrac{14}{17}\))+(\(\dfrac{-5}{13}\)+\(\dfrac{-8}{13}\))+(\(\dfrac{-18}{35}\)+\(\dfrac{17}{-35}\))
= 1+ (-1) + (-1) = -1
f. \(\dfrac{-3}{8}\).\(\dfrac{1}{6}\)+\(\dfrac{3}{-8}\).\(\dfrac{5}{6}\)+\(\dfrac{-10}{16}\)=\(\dfrac{-3}{8}\)(\(\dfrac{1}{6}\)+\(\dfrac{5}{6}\)) + \(\dfrac{-5}{8}\)
=\(\dfrac{-3}{8}\)+\(\dfrac{-5}{8}\)= -1
g. \(\dfrac{-4}{11}\).\(\dfrac{5}{15}\).\(\dfrac{11}{-4}\)=\(\dfrac{5}{15}\)
h.\(\dfrac{7}{36}\)-\(\dfrac{8}{-9}\)+\(\dfrac{-2}{3}\)= \(\dfrac{7}{36}\)-\(\dfrac{-32}{36}\)+\(\dfrac{-24}{36}\)
=\(\dfrac{-49}{36}\)
= 250
Lấy mt ra
\(\left(-375\right)+625=250\)