Question

Tìm x

a, 123 - 5 . ( x + 4 ) = 38

b, ( 3x - 2⁴ ) . 7³ = 2 . 7⁴

c, ( x : 3 - 4 ) . 5 = 15

Answer 1

a) 123 - 5 (x + 4) = 38

5 (x + 4) = 123 - 38

5 (x + 4) = 85

x + 4 = 85 : 5

x + 4 = 17

x = 17 - 4

x = 13

b) (3x - 2⁴) . 7³ = 2 . 7⁴

3x - 2⁴ = 2 . 7⁴ : 7³

3x - 2⁴ = 2 . 7

3x - 16 = 14

3x = 14 + 16

3x = 30

x = 30 : 3

x = 10

c) (x : 3 - 4) . 5 = 15

x : 3 - 4 = 15 : 5

x : 3 - 4 = 3

x : 3 = 3 + 4

x : 3 = 7

x = 7 . 3

x = 21

Answer 2

\(a,123-5.\left(x+4\right)=38\)

\(5.\left(x+4\right)=123-38=85\)

\(x+4=85:5=17\)

\(x=17-4=13\)