Question

Va roog urgeeent!!!
12 Se consideră proporția x supra y egal 5 supra 13.Determinați rapoartele:
a) x+y supray
b) x supra y +x
c) y-x supra x
15 Se consideră proporția x-3y supra x+3y egal 1 supra 5.Determinați raportul 4x+y supra 4x-y. ​

Answer 1

Răspuns:

Explicație pas cu pas:

x/y = 5/13

x = 5y/13

_________

a)

x + y = 5y/13 + y = 5y/13 + 13y/13 = 18y/13

(x + y)/y = (18y/13)/y = 18/13

b)

x/(x + y) = (5y/13) / 18y/13 = 5/18

c)

y - x = y - 5y/13 = 13y/13 - 5y/13 = 8y/13

(y - x)/x = (8y/13) / (5y/13) = 8/5

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(x - 3y)/(x + 3y) = 1/5

5(x - 3y) = x + 3y

5x - 15y = x + 3y

5x - x = 15y + 3y

4x = 18y

x = 18y/4 = 8y/2

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4x + y = 32y/2 + y = 16y + y = 17y

4x - y = 32y/2 - y = 16y - y = 15y

(4x + y)/(4x - y) = 17y/15y = 17/15