Question

Rezolvati în r*r , prin metoda substitutiei, sistemul de ecuatii :
c) x+2y=3, 0.2x-3.5y=4
d) 1/3x+y=2, 2/5x-3y=10

Answer 1

c)x=3-2y
0.2x-3.5y=4
.0.2(3-2y)-3.5y=4
.y=-34/39
0.2x-3.5×(-34/39)=4
x=185/39
(x,y)=(185/39,-34/39)
185/39+2(-34/39)=3
0.2×185/39-3.5×(-34/39)=4
3=3
4=4
rs.(x,y)=(185/39,-34/39)