Bài 1: Thực hiện phép tính: a) 62 . 9 + 50 . 2 – 33 . 3 b) 1200 : 2 + 62 . 21 + 18

Hướng dẫn giải

Bài 1: Thực hiện phép tính:

a) 6² . 9 + 50 . 2 – 3³ . 3 = 36 . 9 + 100 – 81 = 324 + 100 – 81= 343

b) 1200 : 2 + 6² . 2¹ + 18 = 600 + 72 + 18 = 690

c) 3² . 5 + 2³ . 10 – 81 : 3 = 45 + 80 – 27 = 98

d) 5⁹ : 5⁷ + 70 : 14 – 20 = 5^9-7 + 5 -20 = 5² – 15 = 25 – 15 = 10

e) 47 – [[(45 . 2⁴ – 5² . 12) : 14)] = 47 – [(720 – 300) : 14] = 47 – 30 = 17

f) 107 – {38 + [7.3² – 24 : 6 + (9 – 7)³ ]}= 107 – {38 + 63 – 4 + 8} = 107 – 105 = 2

g) 10 – [(8² – 48) . 5 + (2³ . 10 + 8)] : 28

= 10 – [(64 – 48).5 + (8 .10 + 8)] : 28

= 10 – [16.5 + 88] : 28

= 10 – 168 : 28 = 10 – 6 = 4

h) 307 – [(180 – 160) : 2² + 9] : 2

= 307 – [20 : 4 + 9] : 2

= 307 - [5 + 9] : 2 = 307 - 7 = 300

Bài 2: Tính nhanh:

a) 66.25 + 5.66 + 66.14 + 33.66

= 66.(25 + 5 + 14 + 33) = 66. 77 = 5082

b) 136.23 + 136 . 17 – 40 . 36

= 136(23 + 17) – 40 . 36

= 136.40 – 40.36

= 40.(136 – 36)

= 40 . 100 = 400

c) 12 . 35 + 35 . 182 – 35 . 94

= 35.(12 + 182 – 94)

= 35 . 100 = 3500

d) 17 . 93 + 116 . 83 + 17.23

= 17.(93 + 23) + 116 . 83

= 17 . 116 + 116 . 83

= 116.(17 + 83) = 116 . 100 = 11600

Bài 3: Tìm x:

a) 45 – (x + 9) = 6

x + 9 = 45 – 6

x + 9 =39

x = 39 – 9

x = 30

b) 140 : (x – 8) = 7

x – 8 = 140 : 7

x – 8 = 20

x = 20 + 8

x = 28

c) 2(x – 51) = 2.2³ + 20

2(x – 51) = 36

X – 51 = 36 : 2

X – 51 = 18

X = 18 + 51

X = 69

d) 4(x + 41) = 400

x + 41 = 100

x = 100 – 41

x = 59

c) |x + 3| = 2

x + 3 = 2

x = -1

Hoặc x + 3 = -2

X = -5

d) |5x – 3| = 4

5x – 3 = 4

5x = 7

X = 7/5

Hoặc 5x – 3 = -4

5x = -1

X = -1/5