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1: \(=\dfrac{15}{37}\cdot\dfrac{38}{41}-\dfrac{15}{37}\cdot\dfrac{74}{45}-\dfrac{38}{41}\cdot\dfrac{15}{37}-\dfrac{38}{41}\cdot\dfrac{82}{76}\)
\(=\dfrac{-2}{3}-1=-\dfrac{5}{3}\)
2: \(=\dfrac{47}{53}\cdot\dfrac{17}{3}-\dfrac{47}{53}\cdot\dfrac{53}{47}+\dfrac{17}{3}\cdot\dfrac{6}{17}-\dfrac{17}{3}\cdot\dfrac{47}{53}\)
\(=-1+2=1\)
a) 31/23 - ( 7/32 + 8/22)
= 31/23 - 7/32 + 8/23
= ( 31/23 + 8/23 ) - 7/32
= 32/22 - 7/32
= 39/32
Ccá ý khác làm tương tự
Bài 1 : Tính nhanh
a) 16.(38−2)−38(16−1)16.(38−2)−38(16−1)
b) (−41).(59+2)+59(41−2)(−41).(59+2)+59(41−2)
Bài 2 :
Tìm các số x ; y ; x biết rằng :
x + y = 2 ; y + z = 3 ; z + x = -5
Bài 3 : Tìm x ; y ∈∈ Z biết rằng :
( y + 1 ) . xy - 1 ) = 3
a) 123- 5(x+4)=38 b(3x -2^4 )*7^3= 2*7^4
5(x+4) =123-38 (3x-16) = 2*7^4 /7^3
5(x+4)=85 3x-16= 2*7
x+4=85/5 3x-16=14
x+4=17 3x=30
=>x= 13 x= 30/3=10
Nhớ k cho mk nha
a ) \(123-5.\left(x+4\right)=38\)
\(5.\left(x+4\right)=123-38\)
\(5.\left(x+4\right)=85\)
\(x+4=85:5\)
\(x+4=17\)
\(x=17-4\)
a) \(\frac{31}{23}-\left(\frac{7}{32}+\frac{8}{23}\right)=\frac{31}{23}-\frac{7}{32}-\frac{8}{23}=1-\frac{7}{32}=\frac{25}{32}\)
b) \(\left(\frac{1}{3}+\frac{12}{67}+\frac{13}{41}\right)-\left(\frac{79}{67}-\frac{28}{41}\right)\)
\(=\frac{1}{3}+\frac{12}{67}+\frac{13}{41}-\frac{79}{67}+\frac{28}{41}\)
\(=\frac{1}{3}-\left(\frac{79}{67}-\frac{12}{67}\right)+\left(\frac{13}{41}+\frac{28}{41}\right)\)
\(=\frac{1}{3}-1+1=\frac{1}{3}\)
d) \(\frac{1}{7}.\frac{1}{3}+\frac{1}{7}.\frac{-1}{3}+\frac{17}{19}=\frac{1}{7}.\left(\frac{1}{3}-\frac{1}{3}\right)+\frac{17}{19}=\frac{17}{19}\)
e) \(\frac{3}{5}.\frac{7}{9}+\frac{7}{5}.\frac{2}{9}=\frac{7}{5}.\left(\frac{3}{9}+\frac{2}{9}\right)=\frac{7}{5}.\frac{5}{9}=\frac{7}{9}\)
\(123-6.\left(41-38\right)^{^2}\)
\(=123-6.3^2\)
\(=123-6\cdot9\)
\(=123-54\)
\(=69\)
\(123-6\cdot\left(41-38\right)^2\)
\(=123-6\cdot3^2\)
\(=123-6\cdot9\)
\(=123-54\)
\(=69\)