Rozwiąż układy równań
a). {2x + 3y = 7
{ 4x – y = 7
b). { 2x + 4y = 6
{ 3x + 3y = 6
c). { 5x + 2y =17
{ 2x - y = 7
d). { 2x ( x + y ) = 12
{ 3 ( x + y ) = 18
Odpowiedzi
a) {2x + 3y = 7
{12x - 3y = 21
{2x + 3y +12x - 3y = 28
{12x - 3y = 21
{14x = 28
{12x - 3y = 21
{x=2
{24 - 3y = 21
{x=2
{y=1
b) {6x + 12y = 18
{12x + 12y = 24
{6x + 12y = 18
{6x = 6
{6 + 12y = 18
{x = 1
{y = 1
{x = 1
c)
{5x + 2y = 17
{4x - 2y = 14
{9x = 31
{13,(7) - 2y = 14
{x=3,(4)
{2y= 14 - 13,(7)
{x=3,(4)
{y=0,(1)
d) {2x^2 + 2xy = 12
{3x + 3x = 18
{x=1
{y=5
a) y=4x-7
2x+3(4x-7)=7
2x+12x-21=7
14x=28
x=2
4*2-y=7
y=1
b) x=3-2y
3(3-2y)+3y=6
9-6y+3y=6
y=1
2x+4*1=6
2x=2
x=1
c) y=2x-7
5x+2(2x-7)=17
5x+4x-14=17
9x=31
x=31/9
2(31/9)-y=7
y=62/9-7
y=-1/9
d) 3x+3y=18
y=6-x
2x(x+6-x)=12
2x²+12x-2x²=12
12x=12
x=1
3*1+3y=18
3y=15
y=5
