Question

decideti daca marimile a si b din tabel sint invers proportionale: imi trebuie numai ex 1 (a,d)

Answer 1

invers proportional inseamna    ,,a/1/b"( a supra 1 peb)  si se inmulteste a cu inversa lui 1/b  ,adica axb  (sper ca ai inteles...)

a)14/1/12=210/1/0,8=7/1/24=4/1/42=33,6/1/5

[0,8=8/10=4/5  si 33,6=336/10=168/5]

14/1/12=210/1/4/5=7/1/24=4/1/42=168/5/1/5
14x12=210/5/4=7x24=4x42=168/5x5
168=210x4/5=168=168=168  (am simplificat 5 cu 5 la ultima)
(simplificam 210 cu 5)
168=42x4=168=168=168
168=168=168=168=168  =>sunt invers proportionale

d)0,5=5/10=1/2
2,5=25/10=5/2
1,25=125/100=5/4

3/2/1/5/6=2/3/1/14/8=0,5/1/2,5=5/8/1/2=1,25/1
3/2/6/5=2/3/8/14=1/2/5/2=5/8/1/2=5/4/1
3/2x5/6=2/3x14/8=1/2x2/5=5/8x2=5/4x1
[facem simplificari si obtinem:]
1/2x5/3=1/3x7/2=1x1/5=5/4x1=5/4x1
5/6=7/6=1/5=5/4=5/4
aceste nu sunt invers proportionale ,decat ultimele doua