Question

va rog spunetimi rezovarea la
1) folosind proportii derivate,aflati x din:
a)x+1 (supra)x=7 (supra)6
b)x (supra)x+2=7 supra 9
c)x supra 8=x+1 supra 9
2)alfati numerele a,b,c stiind ca:2a supra 3=3b supra 5=5c supra 4 si a+b+c=119
3)stiind ca:31 supra 2b=5 supra 4;3b supra 5c=6 supra 7 si a+b+c=1672,aflati a,b si c
va rog mult de tot sa ma ajutai:(

Answer 1

Exerciţiul 1
$\frac{x+1}{6} = \frac{7+1}{6} = \frac{8}{6} = 1 \frac{2}{6}$

Answer 2

1) a) X + 1/X = 7/6
6(X + 1) = 7X
6X + 6 = 7X
6X + 6 - 7X = 0
-X + 6 = 0
-X = -6/:(-1)
X = 6

b) X/X + 2 = 7/9
9X = 7(X + 2)
9X = 7X + 14
9X -7X - 14 = 0
2X -14 = 0/+ 14
2X = 14/:2
X = 7

c) X/8 = X + 1/9
9X = 8X + 8
9X - 8X - 8 = 0
X- 8 = 0/+ 8
X = 8

3) 31/2b = 5/4
2b × 5 = 31 × 4
10b = 124/:10
b = 12,4

3b/5c = 6/7
3 × 12,4/5c = 6/7
37,2/5c = 6/7
5c × 6 = 37,4 × 7
30c = 260,4/:30
c = 8,68

a + b + c = 1672
a + 12,4 + 8,68 = 1672/- 8,68
a + 12,4 = 1663,32/- 12,4
a = 1650,92

a + b + c = 1672
1650,92 + 12,4 + 8,68 = 1672
1672 = 1672 "Adevarat"