Question

Metoda reducerii! Putin ajutor va rog !

Answer 1

$\left\{\begin{matrix} 2x + 3y = 5 \: | \times 2 \\ 5x + 2y = - 2 \: | \times ( - 3) \end{matrix}\right.$

$\left\{\begin{matrix} 4x + 6y = 10\\ - 15x - 6y = 6\end{matrix}\right.$

$4x - 15x + 6y - 6y = 10 + 6$

$- 11x = 16 \: | \times ( - 1)$

$11x = - 16$

$x = - \frac{16}{11}$

$2x + 3y = 5$

$2 \times ( - \frac{16}{11} ) + 3y = 5$

$- \frac{32}{11} + 3y = 5$

$3y = 5 + \frac{32}{11} \: | \times 11$

$33y = 55 + 32$

$33y = 87$

$y = \frac{87}{33}$

$y = \frac{29}{11}$

Answer 2

2x+3y=5 |(-5)
5x+2y=-2 |2
-10x-15y=-25
10x+4y=-4
adunând
-11y=-29
y=29/11
inlocuind in prima ec a sistemului
2x=5-3×29/11
22x=55-87
22x=-32
x=-32/22
x=-16/11
verif:
5×(-16)/11+2×29/11=-80+58/11=-22/11=-2