Odpowiedzi

2010-04-14T22:14:02+02:00
1)
{x²-y²=12
{x-y=4 => x=4+y

(4+y)²-y²=12
16+8y+y²-y²=12
16+8y=12
8y=-4
y=-0,5

x=4-0,5
x=3,5

{x=3,5
{y=-0,5


2)
{4x²-y²=12
{2x-y=4 => y=2x-4

4x²-(2x-4)²=12
4x²-(4x²-16x+16)=12
4x²-4x²+16x-16=12
16x-16=12
16x=20
x=1,75

y=2*1,75-4
y=-0,5

{x=1,75
{y=-0,5