Question

Rezolvati in multimea numerelor naturale:
a) 2(x + 13) < 145 - 103

b) 3(x + 21) < 64

c) 3 •(x - 2) + 29 = 59

d) 12 •(5 - x) + 31 = 115

Answer 1

a)2x +26  < 42

2x < 42-26

2x < 16  |:2

x < 8   =>  x={0,1,2,3,4,5,6,7}
x∈N

b)3x+ 63 < 64

3x < 64 -63

3x < 1 

x < 1/3  =>  x={0}
x∈N

c)3x-6 +29 =59

3x=59-29+6

3x=36 |:3

x=12

d)60-12x +31 =115

91 -12x =115

-12x = 115-91

-12x= 24 |:12

-x = 2

x= -2
x∈ N       =>x={Ф}