-38

29

30

104

19

24

a) 71-(33+x) = 76

71-33-x=76

38-x=76

x = -38

các bài cn lại bn lm tương tự nha!
 

  65 . (- 45 ) – 35. 45 + 24 .( -21 )+ 76.( -21 )

=65.(-1).45-35.45+24.(-21)+76.(-21)

=45.(-65-35)+(-21).(24+76)

=45.(-100)+(-21).100

=-4500-2100

=-6600

65 . (- 45 ) – 35. 45 + 24 .( -21 )+ 76.( -21 )

= ( 65 + 35 ) . ( 76 + 24 ) . ( -21) - (-21) . ( 45 + (-45)

= 100 . 100 . 0 .0

= cuối cùng thì đều bằng 0

giúp mình với

45 . 76 + 24 . 175 – 24 . 130

= 45 . 76 + 24. ( 175 - 130 )

= 45 . 76 + 24 . 45

= 45 . (76 + 24)

= 45 . 100

= 4500

# HOK TỐT #

\(76-|x|=45\)

\(|x|=31\)

\(\Rightarrow\orbr{\begin{cases}x=31\\x=-31\end{cases}}\)

76 - |x| = 45
        |x| = 76 - 45
        |x| = 31
=> x ∈ {31;-31}
Vậy x ∈ {31;-31}

\(=\dfrac{15}{37}\cdot\dfrac{38}{41}-\dfrac{15}{37}\cdot\dfrac{74}{45}-\dfrac{38}{41}\cdot\dfrac{15}{37}-\dfrac{38}{41}\cdot\dfrac{82}{76}\)

\(=\dfrac{-1}{3}\cdot2-\dfrac{1}{2}\cdot2=-\dfrac{2}{3}-1=-\dfrac{5}{3}\)

a ) \(4x+5y=76\Leftrightarrow5y=76-4x=4\left(19-x\right)\)

Do \(4\left(19-x\right)⋮4\forall x\in N\) nên \(5y⋮4\) mà \(\left(4;5\right)=1\) nên \(y⋮4\) (1)

Từ \(4x+5y=76\forall x;y\in N\Rightarrow5y\le76\Rightarrow y\le\frac{76}{5}=15,2\) (2)

Từ (1) ; (2) \(\Rightarrow y=\left\{0;4;8;12\right\}\)

Với \(y=0\Rightarrow4x=76\Rightarrow x=19\left(TM\right)\)

Với \(y=4\Rightarrow4x+20=76\Rightarrow x=\frac{76-20}{4}=14\left(TM\right)\)

Với \(y=8\Rightarrow4x+40=76\Rightarrow x=\frac{76-40}{4}=9\left(TM\right)\)

Với \(y=12\Rightarrow4x+60=76\Rightarrow x=\frac{76-60}{4}=7\left(TM\right)\)

Vậy \(\left(x;y\right)=\left\{\left(0;19\right);\left(14;4\right);\left(9;8\right);\left(7;12\right)\right\}\)

a ) x = − 91 60 . b ) x = − 8 9 . c ) x = 35 19 . d ) x = 3 7 .

help my

a; 2³.17 + 2³.83 - 14

= 2³.(17 + 83) - 14

= 8.100 - 14

= 800 - 14

= 786 

b; -176 + 197 - (-76 + 97)

= -176 + 197 + 76 - 97

= -(176 - 76) + (197 - 97)

= - 100 + 100

= 0 

c; 2022 - [45 - (6 - 1)² ] + 2021⁰

= 2022 - [45 - 5²] + 1

= 2022 + 1 - [45 - 25] 

= 2023 - 20

= 2003