a)-22: b)35: c)84

a)-Ix-3I+16=4

-Ix-3I=4-16

-Ix-3I=-12

-IxI=-12+3

-IxI=-9

x=-9

b)3-(17-x)=289-(36+289)

3-(17-x)=289-325

3-(17-x)=-36

(17-x)=3-(-36)

(17-x)=39

x=17-39

x=-22

c)25-(x+5)=415-(15-415)

25-(x+5)=415-(-400)

25-(x+5)=815

(x+5)=25-815

(x+5)=-790

x=(-790)-5

x=-795

d)34+(21-x)=(3747-30)-3746

34+(21-x)=3717-3746

34+(21-x)=-29

31+x=21-(-29)

31+x=50

x=50-31

x=19

a) 3 - (17 - x) = 289 - (36 + 289)

3 - (17 - x) = 289 - 325

3 - (17 - x) = -36

17 - x = -36 - 3

17 - x = -39

x = -39 + 17

x = -22

b) 25 - (x + 5) = -415 - (15 - 415)

25 - (x + 5) = -415 - 400

25 - (x + 5) = -15

- (x + 5) = -15 - 25

- (x + 5) = -40

x + 5 = 40

x = 40 - 5

x = 35

c) 34 + (21 - x) = (3747 - 30) - 3746

34 + 21 - x = (3747 - 30) - 3746

55 - x = -29

x = 55 - (-29)

x = 84

k) 3 - ( 17 - x ) = 289 - ( 36 + 289 )

3 - 17 + x = 289 - 36 - 289

x = 289 - 36 - 289 - 3 + 17

x = -22

n) 25 - ( x + 15 ) = ( -415 ) - ( 15 - 415 )

25 - x - 15 = -415 - 15 + 415

25 - x - 15 = -15

25 - 15 + 15 = -x

-x = 25

=> x = -25

m) 34 + ( 21 - x ) = ( 3747 - 30 ) - 3747

34 + 21 - x = 3747 - 30 - 3747

34 + 21 - x = -30

34 + 21 + 30 = -x

-x = 85

=> x = -85

r) Hình như thiếu đề thì phải

HỌC TỐT !

trả lời :

mấy câu kia bạn tham khảo bạn I love You nha

còn câu r) thiếu đề x+2+15:|-3|=? ( chưa có kết quả)

học tốt

1,

a) |x| + |y + 1| =0

Ta có: |x| \(\ge\) 0 (Với x \(\in\) Z)

|y + 1| \(\ge\) 0 (Với y\(\in\) Z)

\(\Rightarrow\) |x| + |y + 1| \(\ge\) 0

Dấu "=" xảy ra (=):

\(\left\{\begin{matrix}\left|x\right|=0\\\left|y+1\right|=0\end{matrix}\right.\Rightarrow\left\{\begin{matrix}x=0\\y+1=0\end{matrix}\right.\Rightarrow}\left\{\begin{matrix}x=0\\y=0-1\end{matrix}\right.\Rightarrow}\left\{\begin{matrix}x=0\\y=-1\end{matrix}\right.\)

Vậy x = 0; y = -1

b) (2 - x)⁴ = 81

\(\Rightarrow\) (2 - x)⁴ = 3⁴ = (-3)⁴

\(\Rightarrow\) \(\left[\begin{matrix}2-x=3\\2-x=-3\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=2-3\\x=2-\left(-3\right)\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=-1\\x=5\end{matrix}\right.\)

Vậy: x \(\in\) {-1; 5}

c) |x - 1| + (-3) = 17

\(\Rightarrow\) |x - 1| = 17 - (-3)

\(\Rightarrow\) |x - 1| = 20

\(\Rightarrow\left[\begin{matrix}x-1=-20\\x-1=20\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=-20+1\\x=20+1\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=-19\\x=21\end{matrix}\right.\)

Vậy: x \(\in\) {-19; 21}

d) 3 - (17 - x) = 289 - (36 + 289)

\(\Rightarrow\) 3 - (17 - x) = 289 - 36 - 289

\(\Rightarrow\) 3 - (17 - x) = 289 - 289 - 36

\(\Rightarrow\) 3 - (17 - x) = 0 - 36

\(\Rightarrow\) 3 - (17 - x) = -36 \(\Rightarrow\) 17 - x = 3 - (-36) \(\Rightarrow\) 17 - x = 39 \(\Rightarrow\) x = 17 - 39 \(\Rightarrow\) x = -22 Vậy: x = -22 e) 25 - (x + 5) = -415 - (15 - 415) \(\Rightarrow\) 25 - (x + 5) = -415 - 15 + 415 \(\Rightarrow\) 25 - (x + 5) = (-415 + 415) - 15 \(\Rightarrow\) 25 - (x + 5) = 0 - 15 \(\Rightarrow\) 25 - (x + 5) = -15 \(\Rightarrow\) x + 5 = 25 - (-15) \(\Rightarrow\) x + 5 = 40 \(\Rightarrow\) x = 40 -5 \(\Rightarrow\) x = 35 Vậy: x = 35 f) 34 + (21 - x) = (3747 - 30) - 3746 \(\Rightarrow\) 34 + (21 - x) = 3747 - 30 - 3746 \(\Rightarrow\) 34 + (21 - x) = 3747 - 3746 - 30 \(\Rightarrow\) 34 + (21 - x) = 1 - 30 \(\Rightarrow\) 34 + (21 - x) = -29 \(\Rightarrow\) 21 - x = -29 - 34 \(\Rightarrow\) 21 - x = -63 \(\Rightarrow\) x = 21 - (-63) \(\Rightarrow\) x = 84 Vậy: x = 84