Question

1. tìm x

a. 71-(33+x)=26

b. (x+73)-26=76

c. 45-(x+9)=6

d. 89-(73-x)=20

e. (x+7)-25=13

f. 198-(x+4)=120

g. 140:(x-8)=7

h. 4(x+41)=400

i. 11(x-9)=77

j. 5(x-9)=350

k. 2x-49=5 .3 mũ 2

l.200-(2x+6)=4 mũ 3

Answer 1

a) 71 - (33 + x) = 26

⇔ 71 - 33 - x = 26

⇔ 38 - x = 26

⇔ x = 38 - 26

⇔ x = 12

b) (x + 73) - 26 = 76

⇔ x + 73 - 26 = 76

⇔ x + 47 = 76

⇔ x = 76 - 47

⇔ x = 29

c) 45 - (x + 9) = 6

⇔ 45 - x - 9 = 6

⇔ 36 - x = 6

⇔ x = 36 - 6

⇔ x = 30

d) 89 - (73 - x) = 20

⇔ 89 - 73 + x = 20

⇔ 16 + x = 20

⇔ x = 20 - 16

⇔ x = 4

e) (x + 7) - 25 = 13

⇔ x + 7 - 25 = 13

⇔ x - 18 = 13

⇔ x = 13 + 18

⇔ x = 31

f) 198 - (x + 4) = 120

⇔ 198 - x - 4 = 120

⇔ 194 - x = 120

⇔ x = 194 - 120

⇔ x = 74

g) 140 : (x - 8) = 7

⇔ x - 8 = 140 : 7

⇔ x - 8 = 20

⇔ x = 20 + 8

⇔ x = 28

h) 4(x + 41) = 400

⇔ x + 41 = 400 : 4

⇔ x + 41 = 100

⇔ x = 100 - 41

⇔ x = 59

i) 11(x - 9) = 77

⇔ x - 9 = 77 : 11

⇔ x - 9 = 7

⇔ x = 7 + 9

⇔ x = 16

j) 5(x - 9) = 350

⇔ x - 9 = 350 : 5

⇔ x - 9 = 70

⇔ x = 70 + 9

⇔ x = 79

k) 2x - 49 = 5.3²

⇔ 2x - 49 = 45

⇔ 2x = 45 + 49

⇔ 2x = 94

⇔ x = 94 : 2

⇔ x = 47

l) 200 - (2x + 6) = 4³

⇔ 200 - 2x - 6 = 64

⇔ 194 - 2x = 64

⇔ 2x = 194 - 64

⇔ 2x = 130

⇔ x = 130 : 2

⇔ x = 65

Answer 2

a) 71 - (33 + x) = 26

⇔ 33+x=71-26

⇔ 33 + x = 45

⇔ x = 45 - 33

⇔ x = 12

Vậy x=12

b) (x + 73) - 26 = 76

⇔ (x + 73) = 76+26

⇔ x + 73 = 102

⇔ x = 102-73

⇔ x = 29

Vậy x=29

c) 45 - (x + 9) = 6

⇔ x + 9 = 45 - 6

⇔ x+9 = 39

⇔ x = 39 - 9

⇔ x = 30

Vậy x=30

Answer 3

d) 89 - (73 - x) = 20

⇔ 73 - x = 89 - 20

⇔ 73 - x = 69

⇔ x = 73 - 69

⇔ x = 4

Vậy x=4

e) (x + 7) - 25 = 13

⇔ x + 7 = 13 + 25

⇔ x + 7 = 38

⇔ x = 38 - 7

⇔ x = 31

Vậy x=31

f) 198 - (x + 4) = 120

⇔ x + 4 = 198 -120

⇔ x + 4 = 78

⇔ x = 78 - 4

⇔ x = 74

Vậy x=74

Answer 4

g) 140 : (x - 8) = 7

⇔ x - 8 = 140 : 7

⇔ x - 8 = 20

⇔ x = 20 + 8

⇔ x = 28

Vậy x=28

h) 4(x + 41) = 400

⇔ x + 41 = 400 : 4

⇔ x + 41 = 100

⇔ x = 100 - 41

⇔ x = 59

Vậy x=59

i) 11(x - 9) = 77

⇔ x - 9 = 77 : 11

⇔ x - 9 = 7

⇔ x = 7 + 9

⇔ x = 16

Vậy x=16

Answer 5

a,71-(33+x)=26

33+x =71-26

33+x =45

x = 45-33

x =12

k, 2x-49 = 5*3 mũ 2

2x- 49 = 5*9

2x -49 = 45

2x = 45 + 49

2x = 94

x = 94/2

x = 47

l,200 - (2x +6) = 4 mũ 3

200 - (2x + 6) = 64

2x + 6 = 200 - 64

2x + 6 = 136

2x = 136 -6

2x = 130

x = 130 / 2

x = 65

Answer 6

X =12;;29;;30;;4;;31;;74;;28;;59;;13;;79;;96;47;;;65