Question

Tìm số tự nhiên x, biết:
a) x + 25 = 40
b) 5.x – 7 = 13
c) 95 – 3.( x + 7) = 23
d) 2.x + 3 mũ 2.3=7 mũ 5 nhân 7 mũ 3

Answer 1

a) x + 25 = 40 

x = 40 - 25

x = 15

b) 5.x - 7 = 13

5.x = 13 + 7 = 20

x = 20 : 5

x = 4

c) 95 - 3.(x+7) = 23

3.(x+7) = 95 - 23 = 72

x + 7 = 72 : 3

x + 7 = 24

x = 24 - 7 

x = 17

d) 2.x + 3² . 3 = 7⁵ . 7³

2.x + 9 . 3 = 7⁵⁺³

2.x + 27 = 7⁸

2.x + 27 = 5764801

2.x = 5764774

x = 5764774 : 2

x = 2882387

Answer 2

a)x=40-25

   x=15

b)5x =13+7

   ⇔x=20:5

       x=4

Answer 3

a) x + 25 = 40 

x = 40 - 25

x = 15

b) 5.x - 7 = 13

5.x = 13 + 7 = 20

x = 20 : 5

x = 4

c) 95 - 3.(x+7) = 23

3.(x+7) = 95 - 23 = 72

x + 7 = 72 : 3

x + 7 = 24

x = 24 - 7 

x = 17

d) 2.x + 3² . 3 = 7⁵ . 7³

2.x + 9 . 3 = 7⁵⁺³

2.x + 27 = 7⁸

2.x + 27 = 5764801

2.x = 5764774

x = 5764774 : 2

x = 2882387