Question

4) (2x+3(x+y)-11=0, 7(x+3y) - 6x + 59 = 0. 195 19 ngr​

Answer 1

{2x+3(x+y)-11=0
{7(x+3y)-6x+59=0

{5х=-3у+11
{7(х+3у)-6х+59

{х= -3/5 у + 11/5
{7(х+3у)-6х+59

7(-3/5 у + 11/5 +3у) -6(-3/5у+11/5)+59=0
84/5 у + 77/5 + 18/5 у - 66/5 + 59=0
102у+306=0
102у=-306
у=-3

х=-3/5 * (-3) + 11/5
х=9/5+11/5
х=4

(х;у)=(4;-3)

Answer 2

$\displaystyle\bf\\\left \{ {{2x + 3(x + y) - 11 = 0} \atop {7(x + 3y) - 6x + 59 = 0 }} \right. \\ \displaystyle\bf\\\left \{ {{2x + 3x + 3y = 11} \atop {7x + 21y - 6x = - 59 }} \right. \\ \displaystyle\bf\\\left \{ {{5x + 3y = 11} \atop {x + 21y = - 59 \: \: | \times( - 5) }} \right. \\ \displaystyle\bf\\ + \left \{ {{5x + 3y = 11} \atop { - 5x - 105y = 295 }} \right. \\ \\ 3y - 105y = 295 + 11 \\ - 102y = 306 \\ y = 306 \div ( - 102) \\ y = - 3 \\ \\ 5x + 3 \times ( - 3) = 11 \\ 5x - 9 = 11 \\ 5x = 11 + 9 \\ 5x = 20 \\ x = 20 \div 5 \\ x = 4$

Ответ: ( 4 ; - 3 )