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Rozwiaz układy równań. Zad 10.6 w załączniku.

Rozwiaz Układy Równań Zad 106 W Załączniku class=

Odpowiedź :

Zadanie 10.6

a) {1,5 - (x - y) = 0,5(y - x) + 2

   {2y - 4 = 4x|: 2

{1,5 - (x - y) = 0,5(y - x) + 2

{y = 2x + 2

{1,5 - (x - (2x + 2)) = 0,5(2x + 2 - x) + 2

{y = 2x + 2

{1,5 - (-x -2x - 2) = 0,5(x + 2) + 2

{y = 2x + 2

{1,5 - (-x - 2) = 0,5x + 1 + 2

{y = 2x + 2

{1,5 + x + 2 = 0,5x + 1 + 2

{y = 2x + 2

{x - 0,5x = 3 - 2 - 1,5

{y = 2x + 2

{0,5x = -0,5|: (0,5)

{y = 2x + 2

{x = -1

{y = 2*(-1) + 2

{x = -1

{y = 0

b) {x + y = 0

   {[tex]\frac{x+2}{4}[/tex] - [tex]\frac{y-3}{3}[/tex] = [tex]\frac{1}{4}[/tex]

{x = -y

{[tex]\frac{x+2}{4}[/tex] - [tex]\frac{y-3}{3}[/tex] = [tex]\frac{1}{4}[/tex]

{x = -y

{[tex]\frac{-y+2}{4}[/tex] - [tex]\frac{y-3}{3}[/tex] = [tex]\frac{1}{4}[/tex]

{x = -y

{[tex]\frac{-y+2}{4}[/tex] - [tex]\frac{y-3}{3}[/tex] = [tex]\frac{1}{4}[/tex]|* 12

{x = -y

{3(-y + 2) - 4(y - 3) = 3

{x = -y

{-3y + 6 - 4y + 12 = 3

{x = -y

{-3y + 6 - 4y + 12 = 3

{x = -y

{-3y - 4y = 3 - 6 - 12

{x = -y

{-7y = -15|: (-7)

{x = -y

{y = [tex]\frac{15}{7}[/tex]

{x = -[tex]\frac{15}{7}[/tex]

{y = [tex]\frac{15}{7}[/tex]

c) {[tex]\frac{3x - y}{2}[/tex] - [tex]\frac{x+4}{4}[/tex] = 4|* 4

   {[tex]\frac{x-y}{2}[/tex] - [tex]\frac{x+5y}{5}[/tex] = 5

{2(3x - y) - (x+1) = 16

{[tex]\frac{x-y}{2}[/tex] - [tex]\frac{x+5y}{5}[/tex] = 5

{6x - 2y - x - 1 = 16

{[tex]\frac{x-y}{2}[/tex] - [tex]\frac{x+5y}{5}[/tex] = 5

{5x = 17 + 2y|: 5

{[tex]\frac{x-y}{2}[/tex] - [tex]\frac{x+5y}{5}[/tex] = 5

{x = [tex]\frac{17}{5}[/tex]+ [tex]\frac{2}{5}[/tex]y

{[tex]\frac{x-y}{2}[/tex] - [tex]\frac{x+5y}{5}[/tex] = 5

{x = [tex]\frac{17}{5}[/tex]+ [tex]\frac{2}{5}[/tex]y

{[tex]\frac{17}{5}[/tex]+ [tex]\frac{2}{5}[/tex]y - y/2 -  

{x = [tex]\frac{17}{5}[/tex]+ [tex]\frac{2}{5}[/tex]y

{[tex]\frac{17 - 3y}{5}[/tex]/2 - [tex]\frac{17 + 27y}{5}[/tex]/5 = 5

{x = [tex]\frac{17}{5}[/tex]+ [tex]\frac{2}{5}[/tex]y

{[tex]\frac{17 - 3y}{10}[/tex] - [tex]\frac{17 + 27y}{25}[/tex] = 5|* 50

{x = [tex]\frac{17}{5}[/tex]+ [tex]\frac{2}{5}[/tex]y

{5(17 - 3y) - 2(17 + 27y) = 250

{x = [tex]\frac{17}{5}[/tex]+ [tex]\frac{2}{5}[/tex]y

{85 - 15y - 34 - 54y = 250

{x = [tex]\frac{17}{5}[/tex]+ [tex]\frac{2}{5}[/tex]y

{-69y = 250 - 51

{x = [tex]\frac{17}{5}[/tex]+ [tex]\frac{2}{5}[/tex]y

{-69y = 199|: (-69)

{x = [tex]\frac{17}{5}[/tex]+ [tex]\frac{2}{5}[/tex]y

{y = -[tex]\frac{199}{69}[/tex]

{x = [tex]\frac{17}{5}[/tex]+ [tex]\frac{2}{5}[/tex] * ( -[tex]\frac{199}{69}[/tex])

{y = -[tex]\frac{199}{69}[/tex]

{x = [tex]\frac{17}{5}[/tex]- [tex]\frac{398}{345}[/tex]

{y = -[tex]\frac{199}{69}[/tex]

{x = [tex]\frac{1173}{345}[/tex] - [tex]\frac{398}{345}[/tex]

{y = -[tex]\frac{199}{69}[/tex]

{x = [tex]\frac{775}{345}[/tex]

{y = -[tex]\frac{199}{69}[/tex]

{x = [tex]\frac{155}{69}[/tex]

{y = -[tex]\frac{199}{69}[/tex]

d) {7x - 3y = [tex]\frac{-5(x+y)}{2}[/tex] - [tex]\frac{5y-25x}{3}[/tex]

   {3[tex]\sqrt{2}[/tex]x + 3

{7x - 3y = [tex]\frac{-5(x+y)}{2}[/tex] - [tex]\frac{5y-25x}{3}[/tex]

{3[tex]\sqrt{2}[/tex]x = - 3

{7x - 3y = [tex]\frac{-5(x+y)}{2}[/tex] - [tex]\frac{5y-25x}{3}[/tex]

{x = -y

{7*(-y) - 3y = [tex]\frac{-5(-y+y)}{2}[/tex] - [tex]\frac{5y-25*(-y)}{3}[/tex]

{x = -y

{-10y = [tex]\frac{-5(0)}{2}[/tex] - [tex]\frac{5y+25y}{3}[/tex]

{x = -y

{-10y = [tex]\frac{0}{2}[/tex] - [tex]\frac{5y+30y}{3}[/tex]

{x = -y

{-10y = - 10y|: (-10)

{x = -y

{y ∈ R

{x = -y