\(\dfrac{8}{18}+\dfrac{12}{27}\)
giúp mk với
\(x+\dfrac{4}{9}+\dfrac{8}{18}+\dfrac{12}{27}+\dfrac{16}{36}=\dfrac{16}{9}\)
giúp mk với ạ
x + 4/9 + 8/18 + 12/27 + 16/36 = 16/9
x + (4/9+12/27)+(8/12+16/36) = 16/9
x + 8/9 + 10/9 = 16/9
x + 2 = 16/9
x = 16/9 - 2
x = -2/18
x+4/9+4/9+4/9+4/9=16/9
x+4/9.4=16/9
x+16/9=16/9
--> x = 0
Phân số \(\dfrac{4}{9}\)bằng phân số nào dưới đây:
a. \(\dfrac{8}{27}\)
b. \(\dfrac{16}{27}\)
c. \(\dfrac{12}{18}\)
d. \(\dfrac{12}{27}\)
\(\dfrac{7}{12}-\dfrac{27}{7}.\dfrac{1}{18}\)
Mn ghi cách làm giúp mình nha
\(=\dfrac{7}{12}-\dfrac{3}{14}=\dfrac{98-36}{168}=\dfrac{62}{168}=\dfrac{31}{84}\)
Tính giá trị của biểu thức: \(M=\dfrac{1+ab}{a+b}-\dfrac{1-ab}{a-b}\) với \(b=\dfrac{3\sqrt{8}-2\sqrt{12}+\sqrt{20}}{3\sqrt{18}-2\sqrt{27}+\sqrt{45}}\)
\(\dfrac{2\sqrt{8}-\sqrt{12}}{\sqrt{18}-\sqrt{48}}-\dfrac{\sqrt{5}+\sqrt{27}}{\sqrt{30}+\sqrt{162}}\)
Ta có: \(\dfrac{2\sqrt{8}-\sqrt{12}}{\sqrt{18}-\sqrt{48}}-\dfrac{\sqrt{5}+\sqrt{27}}{\sqrt{30}+\sqrt{162}}\)
\(=\dfrac{4\sqrt{2}-3\sqrt{2}}{3\sqrt{2}-4\sqrt{2}}-\dfrac{\sqrt{5}+\sqrt{27}}{\sqrt{6}\left(\sqrt{5}+\sqrt{27}\right)}\)
\(=-1-\dfrac{1}{\sqrt{6}}\)
\(=\dfrac{-6-\sqrt{6}}{6}\)
\(\dfrac{2\sqrt{8}-\sqrt{12}}{\sqrt{18}-\sqrt{48}}-\dfrac{\sqrt{5}+\sqrt{27}}{\sqrt{30}+\sqrt{162}}\)
\(=\dfrac{2\sqrt{8}-2\sqrt{3}}{\sqrt{6}\left(\sqrt{3}-\sqrt{8}\right)}-\dfrac{\sqrt{5}+\sqrt{27}}{\sqrt{6}\left(\sqrt{5}+\sqrt{27}\right)}\)
\(=\dfrac{-2}{\sqrt{6}}-\dfrac{1}{\sqrt{6}}=\dfrac{-3}{\sqrt{6}}=\dfrac{-3\cdot\sqrt{6}}{6}=\dfrac{-\sqrt{6}}{2}\)
Cho đẳng thức: (-8).15=12.(-10) Tỉ lệ thức đc suy ra từ đẳng là:
A.\(\dfrac{-18}{12}\)=\(\dfrac{15}{-10}\)
B.\(\dfrac{15}{12}\)=\(\dfrac{-10}{-8}\)
C.\(\dfrac{-8}{-10}\)=\(\dfrac{15}{12}\)
D.\(\dfrac{-8}{15}\)=\(\dfrac{12}{-10}\)
Mong mn giúp đỡ.
Mk đang cần gấp.
Thanks:)
\(\text{B.}\dfrac{15}{12}=\dfrac{-10}{-8}\)
a,\(\dfrac{10+2\sqrt{10}}{\sqrt{5}+\sqrt{2}}=\dfrac{8}{1-\sqrt{5}}\)
b,\(\dfrac{2\sqrt{8}-\sqrt{12}}{\sqrt{18}-\sqrt{48}}-\dfrac{\sqrt{5}+\sqrt{27}}{\sqrt{30}+\sqrt{162}}\)
\(a,Sửa:\dfrac{10+2\sqrt{10}}{\sqrt{5}+\sqrt{2}}+\dfrac{8}{1-\sqrt{5}}\\ =\dfrac{2\sqrt{5}\left(\sqrt{5}+\sqrt{2}\right)}{\sqrt{5}+\sqrt{2}}+\dfrac{8\left(1+\sqrt{5}\right)}{-4}\\ =2\sqrt{5}-2-2\sqrt{5}=-2\\ b,=\dfrac{\sqrt{32}-\sqrt{12}}{\sqrt{18}-\sqrt{48}}-\dfrac{\sqrt{5}+\sqrt{27}}{\sqrt{6}\left(\sqrt{5}+\sqrt{27}\right)}\\ =\dfrac{\sqrt{2}\left(4-\sqrt{6}\right)}{\sqrt{3}\left(\sqrt{6}-4\right)}-\dfrac{1}{\sqrt{6}}=\dfrac{\sqrt{6}}{3}-\dfrac{\sqrt{6}}{6}=\dfrac{2\sqrt{6}-\sqrt{6}}{6}=\dfrac{\sqrt{6}}{6}\)
Tính:
a) \(\dfrac{7}{19}+\dfrac{12}{19}\)
b) \(\dfrac{5}{13}+\dfrac{4}{13}\)
c) \(\dfrac{24}{11}-\dfrac{13}{11}\)
d) \(\dfrac{35}{8}-\dfrac{19}{8}\)
GIÚP MK VỚI HOM NAY MÌNH NÔP RÙI
\(a.\dfrac{7}{19}+\dfrac{12}{19}=\dfrac{7+12}{19}=\dfrac{19}{19}=1\)
\(b.\dfrac{5}{13}+\dfrac{4}{13}=\dfrac{5+4}{13}=\dfrac{9}{13}\)
\(c.\dfrac{24}{11}-\dfrac{13}{11}=\dfrac{24-13}{11}=\dfrac{11}{11}=1\)
\(d.\dfrac{35}{8}-\dfrac{19}{8}=\dfrac{35-19}{8}=\dfrac{16}{8}=2\)
a,\(\dfrac{7}{19}\)+\(\dfrac{12}{19}\)=\(\dfrac{19}{19}\)=1
b,\(\dfrac{5}{13}\)+\(\dfrac{4}{13}\)=\(\dfrac{9}{13}\)
c,\(\dfrac{24}{11}\)-\(\dfrac{13}{11}\)=\(\dfrac{11}{11}\)=1
d,\(\dfrac{35}{8}\)-\(\dfrac{19}{8}\)=\(\dfrac{16}{8}\)=2