Question

1.Stiind ca 12x-5ysupra3x=2supra3,calculation x supra y si x²+xy supra y².
2.Calculati x din proportiile:
a)x-1supra1+½=7/3-1supra3-3/2,x€ Q;
b)2x+1supra4x+3=1/3,x € Q\{-¾}.

Answer 1

1.  (12x -5y)/3x = 2/3         3(12x-5y) = 6x    36x - 15y = 6x    30x = 15y    y = 2x
x/y = x/2x = 1/2    (x² +2x² )/ 4x² = 3x² /4x² = 3/4
2.  a)  2(x-1)/3 = 7/3 - 1/(3/2)        2(x-1)/3 = 7/3 - 2/3     2(x-1)   = 4  x-1 = 2  x =3
b)  (2x+1)/ (4x+3) = 1/3
3(2x+1) = 4x+3      6x+3 = 4x+3    2x = 0  x = 0