\(\frac{1}{2}+\frac{5}{6}-\frac{3}{8}\)
\(\frac{10}{15}.\frac{7}{4}+\frac{7}{4}.\frac{9}{15}-\frac{4}{15}.\frac{7}{4}\)
\(\left(\frac{4}{5}+\frac{1}{2}\right).\left(\frac{3}{13}-\frac{8}{13}\right)\)
Tìm số nguyên x, bt:
a/ 3x-12=30 b/
\(\frac{2}{3}x+\frac{1}{4}=\frac{7}{12}\)
c/ 2x2 =32
giúp em nhé mai em thi!
\(\frac{1}{2}+\frac{5}{6}-\frac{3}{8}\)
\(=\frac{12}{24}+\frac{20}{24}-\frac{9}{24}\)
\(=\frac{23}{24}\)
\(\frac{10}{15}\cdot\frac{7}{4}+\frac{7}{4}\cdot\frac{9}{15}-\frac{4}{15}\cdot\frac{7}{4}\)
\(=\frac{7}{4}\cdot\left(\frac{10}{15}+\frac{9}{15}-\frac{4}{15}\right)\)
\(=\frac{7}{4}\cdot1=\frac{7}{4}\)
\(\left(\frac{4}{5}+\frac{1}{2}\right)\left(\frac{3}{13}-\frac{8}{13}\right)\)
\(=\left(\frac{8}{10}+\frac{5}{10}\right)\cdot\left(-\frac{5}{13}\right)\)
\(=\frac{13}{10}\cdot\left(-\frac{5}{13}\right)=-\frac{1}{2}\)
a, 3x-12 = 30
=> 3x = 30 + 12
=> 3x = 42
=> x = 42 : 3 = 14
Vậy x = 14
b, \(\frac{2}{3}x+\frac{1}{4}=\frac{7}{12}\)
\(\Rightarrow\frac{2}{3}x=\frac{7}{12}-\frac{1}{4}\)
\(\Rightarrow\frac{2}{3}x=\frac{7}{12}-\frac{3}{12}\)
\(\Rightarrow\frac{2}{3}x=\frac{1}{3}\)
\(\Rightarrow x=\frac{1}{3}\div\frac{2}{3}\Rightarrow\frac{1}{3}\cdot\frac{3}{2}=\frac{1}{2}\)
Vậy x = \(\frac{1}{2}\)
c, 2x2 = 32
=> x2 = 32 : 2
=> x2 = 16
=> x2 = 42
=> x = 4
Vậy x = 4
cái phép tính thứ nhất lm sao đổi ra mẫu 24 đc z anh?
\(=\frac{1}{2}+\frac{5}{6}+\frac{-3}{8}\)
\(=\frac{12}{24}+\frac{20}{24}+\frac{-9}{24}\)
\(=\frac{-23}{24}\)
1/2 + 5/6 - 3/8
= 12/24 + 20/24 - 9/24
= 12 + 20 - 9 / 24
= 23/24
10/15 . 7/4 + 7/4 . 9/15 - 4/15 . 7/4
= 7/4 . ( 10/15 + 9/15 - 4/15 )
= 7/4 . 1
= 7/4
#Louis
\(\frac{10}{15}.\frac{7}{4}+\frac{7}{4}.\frac{9}{15}-\frac{4}{15}.\frac{7}{4}\)
\(=\frac{7}{4}.\left(\frac{10}{15}+\frac{9}{15}-\frac{4}{15}\right)\)
\(=\frac{7}{4}.1\)
\(=\frac{7}{4}\)
Study well ! >_<
\(\frac{1}{2}+\frac{5}{6}-\frac{3}{8}\)
\(=\frac{12}{24}+\frac{20}{24}-\frac{9}{24}\)
\(=\frac{12+20-9}{24}\)
\(=\frac{23}{24}\)
Study well ! >_<
a) 3x - 12 = 30
3x = 30 + 12
3x = 42
x = 42 : 3
x = 14
b) 2x2 = 32
x2 = 32 : 2
x2 = 16
=> x = 4 hoặc x = -4
Vậy....
#Louis
\(\left(\frac{4}{5}+\frac{1}{2}\right).\left(\frac{3}{13}-\frac{8}{13}\right)\)
\(=\left(\frac{8}{10}+\frac{5}{10}\right).\left(\frac{-5}{13}\right)\)
\(=\frac{13}{10}.\frac{-5}{13}\)
\(=\frac{-5}{10}=\frac{-1}{2}\)
Study well ! >_<
a, 3x - 12 = 30
=> 3x = 30 + 12
=> 3x = 42
=> x = 42 : 3
=> x = 14
Study well ! >_<
a, x-12=30
=>x=42
c, 2X2=32
=>x2=16
=> x=4 hoặc x=-4