Question

1.Aflați x din proporțiile:
a) x+1/2=6/3
b) 13/21=10x-21/8x-16
2.Daca x/y=7/9 calculati 5x+2y/2x-y

Answer 1

Răspuns:

Explicație pas cu pas:

(x + 1)/2 = 6/3

3(x + 1) = 2*6

3x + 3 = 12

3x = 12 - 3 = 9

x = 9 : 3 = 3

_________________

13/21 = (10x - 21)/(8x - 16)

13(8x - 16) = 21(10x - 21)

104x - 208 = 210x - 441

441 - 208 = 210x - 104x

233 = 106x

x = 233/106

___________________

x/y = 7/9

x = 7y/9

5x + 2y = 35y/9 + 18y/9 = 53y/9

2x - y = 14y/9 - 9y/9 = 5y/9

(5x + 2y)/(2x - y) = 53y/9 : 5y/9 = 53y/9 * 9/5y = 53/5