a: \(\dfrac{5}{7}+\dfrac{-3}{11}+\dfrac{2}{7}+\dfrac{-8}{11}\)

\(=\left(\dfrac{5}{7}+\dfrac{2}{7}\right)+\left(\dfrac{-3}{11}+\dfrac{-8}{11}\right)\)

\(=\dfrac{7}{7}-\dfrac{11}{11}=1-1=0\)

b: \(\dfrac{5}{11}-\dfrac{3}{7}-\dfrac{4}{7}+\dfrac{6}{11}\)

\(=\left(\dfrac{5}{11}+\dfrac{6}{11}\right)-\left(\dfrac{3}{7}+\dfrac{4}{7}\right)\)

\(=\dfrac{11}{11}-\dfrac{7}{7}=1-1=0\)

c: \(\dfrac{9}{13}-\dfrac{3}{8}-\dfrac{5}{8}-\dfrac{22}{13}\)

\(=\left(\dfrac{9}{13}-\dfrac{22}{13}\right)+\left(-\dfrac{3}{8}-\dfrac{5}{8}\right)\)

\(=-\dfrac{13}{13}-\dfrac{8}{8}=-1-1=-2\)

d: \(\dfrac{3}{16}-\dfrac{19}{16}+\dfrac{2}{3}+\dfrac{-8}{3}\)

\(=\left(\dfrac{3}{16}-\dfrac{19}{16}\right)+\left(\dfrac{2}{3}-\dfrac{8}{3}\right)\)

\(=-\dfrac{16}{16}+\dfrac{-6}{3}=-1-2=-3\)

khoảng 40-45

40-45 kg

ai bít

Không biết thì trả lời làm giề

\(1=\dfrac{100}{100};\dfrac{5}{4}=\dfrac{125}{100}\)

=>8 phân số nằm giữa là \(\dfrac{101}{100};\dfrac{102}{100};\dfrac{105}{100};\dfrac{107}{100};\dfrac{110}{100};\dfrac{112}{100};\dfrac{115}{100};\dfrac{116}{100}\)

\(2^{x+1}=640-2^{x+3}\)

=>\(2^{x+1}+2^{x+3}=640\)

=>\(2^x\cdot2+2^x\cdot8=640\)

=>\(10\cdot2^x=640\)

=>\(2^x=64=2^6\)

=>x=6

còn lại số kg đường là:

165,5-(12+12x3/2)=135,5(kg)

Buổi chiều bán được:

\(12\times\dfrac{3}{2}=18\left(kg\right)\)

Khối lượng đường còn lại là:

165,5-12-18=165,5-30=135,5(kg)

511+−37+611+23+−47=(511+611)+(−37+−47)+23=23

=0

Long béo

Long béo

Cho:

Điền hệ số thích hợp vào ô trống.
$P(x)+Q(x)=$ $($$x^3$$)$ $+$ $($$x^2$$)$$+$ $($$x$$)$ $+$ $($$)$

P(x)+Q(x)

\(=3x^2-3x+6+4x^3-5x^2+x-3\)

\(=4x^3-2x^2-2x+3\)

\(\dfrac{18}{8}+\dfrac{-3}{8}-\dfrac{2}{5}+\dfrac{-3}{5}\)

\(=\left(\dfrac{18}{8}-\dfrac{3}{8}\right)+\left(-\dfrac{2}{5}-\dfrac{3}{5}\right)\)

=\(-\dfrac{5}{5}+\dfrac{15}{8}=-1+\dfrac{15}{8}=\dfrac{7}{8}\)