Question

a b c sunt direct proportionale cu 2 3 5 determinati stiind ca 2a-3b+4c=120​

Answer 1

Răspuns:

a,b,c.....dp....2,3,5

a/2=b/3=c/5 notam k

a/2=K/1.......a=2k

.....b=3k

.....c=5k

2×2k-3×3k+4×5k=120

4k-9k+20k=120

-5k+20k=120

15k=120/15

k=8

a=2×8

=16

b=3×8

=24

c=5×8

=40

Answer 2

Răspuns:

Explicație pas cu pas:

[ a; b; c] d.p. [ 2; 3; 5]

⇒   a/2 = b/3 = c/5 = k → coeficient de proportionalitate

⇒  a/2 = k ⇒  a = 2 k

     b/3= k ⇒  b = 3 k

     c/5 = k ⇒ c = 5 k

_________________

2 a - 3 b + 4 c = 120

2 × 2 k - 3 × 3 k + 4 × 5 k = 120

4 k - 9 k + 20 k = 120

15 k = 120

k = 120 : 15          ⇒     k = 8

_______________________

a = 2 k = 2 × 8    ⇒    a = 16

b = 3 k = 3 × 8    ⇒   b = 24

c = 5 k = 5 × 8    ⇒   c = 40