Question

Cine ma poate ajuta repede va rog muult!!!
Am mare nevoie va rog mult!!!
​Am nevoie până mâine!!

Answer 1

Răspuns:

Explicație pas cu pas:

1a) {2x+3y = 1

     {-3x-y = 2  I·3 =>

----

    {2x+3y = 1

    {-9x-3y = 6

   =========

    -7x = 7 => x = -1

y = -3x-2 = (-3)·(-1) - 2 = 3-2 => y = 1

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

    {3(x-2)+5(x+y) = 9  <=>

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  {2x-2-x-y = -3

  {3x-6+4x+4y = 9 <=>

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{x-y = -1      I·4 =>

{7x+4y = 15

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{4x-4y = -4

{7x+4y = 15

==========

11x = 11 => x = 1

y = x+1 => y = 2

2a) {³⁾(x+y)/2 + ²⁾(x-y)/3 = ⁶⁾1

     {(2x-y+1)/4 = ²⁾(x+y-2)/2  =>

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{3x+3y+2x-2y = 6

{2x-y+1 = 2x+2y-4  <=>

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{5x+y = 6

{3y = 5  => y = 5/3

x = (6-y)/5 = (6-5/3)/5 = > x = 13/15

2b) {(x+1)² = (x+2)(x-3)+y

     {(x-2)(y+2) = xy-10 <=>

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{x²+2x+1 = x²-x-6+y

{xy+2x-2y-4 = xy-10 <=>

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{3x-y = -7

{2x-2y = -6  I:(-2)   =>

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{3x-y = -7

{-x+y = 3

=======

2x = -4  => x = -2

y = x+3 => y = 1

4) {2ax-b = y+3

   {x+2a = 4b+2y  

(x ; y) = (1 ; 1)  => x = 1 ; y = 1  =>

{2a-b = 4

{2a+1 = 4b+2  <=>

----

{2a-b = 4

{2a-4b = 1  I·(-1) =>

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{2a-b = 4

{-2a+4b = -1

=========

3b = 3 => b = 1

2a = b+4 = 5 => a = 5/2

Answer 2

Răspuns:

Explicație pas cu pas: