math....!!*

xy = 12 ----- (1)
3x - 2y = 14 -----(2)

from (1),
xy = 12
x = 12/y --- (3)
put (3) into (2),
3(12/y) - 2y = 14
36/y - 2y = 14
36 - 2y2 = 14y
y2 + 7y - 18 = 0
(y + 9)( y - 2) = 0
therefore,
y + 9 = 0
y = -9
x = 12/y = 12/-9 = - 4/3
OR
y - 2 = 0
y = 2
x = 12/y = 12/2 = 6
Ans: x = -4/3 , y = -9 and x = 6 , y = 2

xy = 12------------1
3x - 2y = 14-------------2
1,xy=12
x=12/y-------------3
sub.2 into 3
3(12/y)-2y=14
36-2y^2=14y
-2y^2-14y+36=0
(2y-4)(y+9)=0
y=2 or y=-9
sub.y=2 into1
2x=12
x=6
sub. y=-9 into 1
-9x=12
x=-4/3
so x= 4/3 or 6, y=2 or y=-9

x=6; y=2

Proof: 6(2)=12
3(6)-2(2)=14

如果日後要問功課，請用[email protected]
註明年級及課題