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a: \(=\dfrac{1}{3}-\dfrac{37}{100}+\dfrac{1}{8}-\dfrac{32}{25}+\dfrac{-5}{2}+\dfrac{3}{2}\)
\(=\dfrac{1}{3}+\dfrac{1}{8}-1-\dfrac{37}{100}-\dfrac{128}{100}\)
\(=\dfrac{8+3-24}{24}-\dfrac{165}{100}\)
\(=\dfrac{-263}{120}\)
b: \(=\dfrac{5}{22}+\dfrac{3}{13}-\dfrac{13}{8}-\dfrac{2}{11}+\dfrac{3}{2}\)
\(=\dfrac{5}{22}-\dfrac{4}{22}-\dfrac{13}{8}+\dfrac{12}{8}+\dfrac{3}{13}\)
\(=\dfrac{1}{22}-\dfrac{1}{8}+\dfrac{3}{13}=\dfrac{173}{1144}\)
\(B=\left(1-\frac{1}{12}\right)\left(1-\frac{1}{13}\right)\left(1-\frac{1}{14}\right)\)
\(=>B=\frac{11}{12}\cdot\frac{12}{13}\cdot\frac{13}{14}\)
\(=>B=\frac{11\cdot12\cdot13}{12\cdot13\cdot14}=\frac{11}{14}\)
y+z+1x=x+z+2y=x+y−3z=1x+y+zy+z+1x=x+z+2y=x+y−3z=1x+y+z(đk x+y+z≠0≠0
⇒y+z+1x=x+z+2y=x+y−3z=y+z+1+x+z+2+x+y−3x+y+z=2⇒y+z+1x=x+z+2y=x+y−3z=y+z+1+x+z+2+x+y−3x+y+z=2
⇒1x+y+z=2⇒x+y+z=0,5⇒1x+y+z=2⇒x+y+z=0,5
⇒y+z=0,5−x,x+z=0,5−y,x+y=0,5−z⇒y+z=0,5−x,x+z=0,5−y,x+y=0,5−z
⇒0,5−x+1x=2⇒1,5−xx=2⇒1,5−x=2x⇒3x=1,5⇒x=12⇒0,5−x+1x=2⇒1,5−xx=2⇒1,5−x=2x⇒3x=1,5⇒x=12
⇒0,5−y+2y=2⇒2,5−yy=2⇒2,5−y=2y⇒3y=2,5⇒y=56⇒0,5−y+2y=2⇒2,5−yy=2⇒2,5−y=2y⇒3y=2,5⇒y=56
⇒z=0,5−12−56=−56⇒z=0,5−12−56=−56
Vậy x=12,y=56,z=−56
Bài 1 :
a) 16.(38−2)−38(16−1)
= 16 * 38 - 2* 16 - 16 *38 + 38
= - 32 +38
= 6
b) (−41).(59+2)+59(41−2)
= (-41) * 59 - 41 *2 + 41 * 59 - 59 *2
= 2(-41 - 59)
= 2* (-100)
= -200
Bài 2 :
Tìm các số x ; y ; x biết rằng :
x + y = 2 ; y + z = 3 ; z + x = -5
=> 2(x+ y + z)= 2+3+(-5)= 0
=> x+y +z =0
=> z= (x+y+z) -(x+y) = 0-2 =-2
x= (x+y+z) -(y+z) = 0-3 =-3
y = (x+y+z) - (x+z) = 0 -(-5) =0+5 =5
Vậy x= -2 ; y=-3 ; z=5
Bài 3 : Tìm x ; y ∈ Z biết rằng :
( y + 1 ) . xy - 1 ) = 3
(sao có 3 dấu ngoặc z?)
Bài 3 : Tìm x ; y ∈∈ Z biết rằng :
( y + 1 ) . ( xy - 1 ) = 3
a: \(=\dfrac{1}{3}-\dfrac{37}{100}+\dfrac{1}{8}-\dfrac{32}{25}-\dfrac{5}{2}+\dfrac{3}{2}\)
\(=\dfrac{11}{24}+\left(-\dfrac{37}{100}+\dfrac{1}{8}-1\right)\)
\(=\dfrac{11}{24}-\dfrac{249}{200}=-\dfrac{59}{75}\)
b: \(=\dfrac{5}{22}+\dfrac{3}{13}-\dfrac{13}{8}-\dfrac{2}{11}+\dfrac{3}{2}\)
\(=\dfrac{5}{22}-\dfrac{4}{22}+\dfrac{3}{13}-\dfrac{13}{8}+\dfrac{12}{8}\)
\(=\dfrac{1}{22}+\dfrac{3}{13}-\dfrac{1}{8}=\dfrac{173}{1144}\)