Răspuns:
Explicație pas cu pas:
a)
{2x+4y = 6 I ·3
{6x+3y = 5 =>
{6x+12y = 18
{6x+3y = 5
--------------------
/ 9y = 13 => y = 13/9
6x + 3·13/9 = 5 =>
6x = 5-13/3 = 2/3
x = (2/3):6 = 2/3 · 1/6 = 2/18 => x = 1/9
b)
{8a-4b = -4
{2a+5b = 2 I ·4 =>
{8a-4b = -4
{8a+20b=8
---------------
/ 16b = 4 => b = 4/16 => b = 1/4
8a - 4·1/4 = -4 => 8a = -3 => a = -3/8
