Question

Tìm số nguyên x:

a, |2x+1|-19= -7

b, -28 - 7.|-3x+15|= -70

c, |18-2.|-x+5||= 12

d, 12-2.(-x+3)² = -38

e, -20+3.(2x+1)³ = -101

Answer 1

a, |2x+1| - 19 = -7

|2x+1| = 12

TH1: 2x + 1 = 12

2x = 11

x = \(\frac{11}{2}\)

TH2: 2x + 1 = -12

2x = -13

x = \(\frac{-13}{2}\)

b, -28 - 7.|-3x+15| = -70

-7.|-3x+15| = -42

|-3x+15| = 6

TH1: -3x + 15 = 6

-3x = -9

x = 3

TH2: -3x + 15 = -6

-3x = -21

x = 7

d, 12 - 2( -x + 3)² = -38

-2( -x + 3)² = -50

( -x + 3)² = 25

( -x + 3)² = +- 5²

-x + 3 = +- 5

TH1: -x + 3 = 5

-x = 2

x = -2

TH2: -x + 3 = -5

-x = -8

x = 8

e, -20 + 3(3x+1)³ = -101

3(3x+1)³ = -81

(3x+1)³ = -27

(3x+ 1)³ = -3³

3x + 1 = -3

3x = -4

x = \(\frac{-4}{3}\)

Chúc bạn học tốt !

Answer 2

hello

Answer 3

a, |2x+1|-19= -7

|2x+1|=-7+(-19) |2x+1|=-26 truong hop 1: 2x+1=-26 2x=-26-1 2x=-27 x=-27:2( vo li) truong hop 2 2x+1=26 2x=26-1 2x=25 x=25:2 ( vo li) Vay x ko co gia tri nao thoa man

Answer 4

b, -28 - 7.|-3x+15|= -70

7.|-3x+15|= -28+70

7.|-3x+15|=42

|-3x+15|=42:7

|-3x+15|=6

truong hop 1

-3x+15=6

-3x=6-15

-3x=-9

x=-9:(-3)

x=3

Vay x=3

truong hop 2

-3x+15=-6

-3x=-6-15 -3x=-21 x=-21:(-3) x=7 vay x =7 Vay x \(\in\left\{3;7\right\}\)

Answer 5

c, |18-2.|-x+5||= 12

theo de bai ta co : truong hop 1 18-2.|-x+5|= 12 2|-x+5|= 18-12 2.|-x+5|=6 |-x+5|=6:2 |-x+5|=3 \(\Rightarrow\left[{}\begin{matrix}\text{-x+5=3}\\\text{-x+5=-3}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}-x=3-5\\-x=-3-5\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}-x=-2\\-x=-8\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=-2\\x=-8\end{matrix}\right.\) Vay x\(\in\left\{-2;-8\right\}\) truong hop 2 18-2.|-x+5|= -12 2|-x+5|= 18+12 2.|-x+5|=30 |-x+5|=30:2 |-x+5|=15 \(\Rightarrow\left[{}\begin{matrix}\text{-x+5=15}\\\text{-x+5=-15}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}-x=15-5\\-x=-15-5\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}-x=10\\-x=-20\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=-10\\x=-20\end{matrix}\right.\) vay x \(\in\left\{-10;-20\right\}\) Vay tu tap hop 1;2 ta co x\(\in\left\{-2;-8;-10;-20\right\}\)

Answer 6

d, 12-2.(-x+3)² = -38

2.(-x+3)2 =12+38

2.(-x+3)2 =50

(-x+3)² =50:2

(-x+3)² =25

(-x+3)² =\(5^2\)

=>-x+3=5

-x=5-3

-x=2

x=-2

vay x=-2

Answer 7

e, -20+3.(2x+1)³ = -10

3.(2x+1)3 =-101-(-20)

3.(2x+1)³ =-81

(2x+1)³ =-81:3

(2x+1)³ =-27

(2x+1)³ =\(-3^2\)

=>2x+1=-3

2x=-3-1

2x=-4

x=-4:2

x=-2

Vay x =-2

Answer 8

neu muon link cho mik thi link het nha :v

Answer 9

sao @Xích U Lan lai dc cong dong lua chon ma trong do x thuoc Z ???