Question

Va rog urgent! Dau coroana.

Se considera multimea A = {-3; -2; -1; 0; 1; 2; 3; 4}. Aflati elementul multimii mii A, care scris in locul lui x, formeaza o propozitie adevarata

a) x-(-5)=3

b) x- (8+) = - 9

c) - 12-x= - 9

d) 16-x=19

e) - 6-x= -8

f) x-8= -9

g) -2=x - 3

h) -7= - 8-x

i) 19-x=1

j) 21=6-x

k) x - (1 - +) < -7

l) 20 - x > 20 ( la acest exercitiu semnul > are linie jos)

Answer 1

Explicație pas cu pas:

a) x - (- 5) = 3

x + 8 = 3 <=> x = 3 - 8

=> x = - 2 ∈ A

b) x - (+ 8) = - 9

x -8 = -9 <=> x = - 9 + 8

=> x = - 1 ∈ A

c) - 12 - x = - 9

x = - 12 + 9 => x = - 3 ∈ A

d) 16 - x = 19

x = 16 - 19 => x = - 3 ∈ A

e) - 6 - x = - 8

x = - 6 + 8 => x = 2 ∈ A

f) x - 8 = - 9

x = - 9 + 8 => x = - 1 ∈ A

g) - 2 = x - 3

x = - 2 + 3 => x = 1 ∈ A

h) - 7 = - 8 - x

x = - 8 + 7 => x = - 1 ∈ A

i) 19 - x = 1

x = 19 - 1 => x = 18 ∉ A

j) 21 = 6 - x

x = 21 - 6 => x = 15 ∉ A

k) x - (1 - +) < -7

??

l) 20 - x ≥ 20

x ≤ 20 - 20 => x ≤ 0

x ∈ {-3; -2; -1; 0}