2007-06-16 07:56:55 · 3 answers · asked by tony f 1 in Science & Mathematics ➔ Mathematics
.-4x+5y=-14 ...1st
x+4y=-7
x= -7-4y
substituting in 1st
-4(-7-4y) +5y= -14
28+16y+5y= -14
21y = 14
y=21/14
= 3/2 = 1.5
so x =-7-4(3/2)
= -13
2007-06-16 07:59:36 · answer #1 · answered by sweet n simple 5 · 0⤊ 0⤋
(1) -4x + 5y = -7
(2) -14x + 4y = -7
Multiply (1) by (-7)
-7 * (-4x + 5y) = (-7) * (-7)
28x - 35 y = 49
Mulitply (2) by (2)
2 * (-14x + 4y) = 2 * (-7)
-28x + 8y = -14
Add them together
28x - 35 y = 49
-28x + 8y = -14
------------------------
- 27y = 35
y = - 35/27
from (1):
4x = 5y + 7
4x = 5 (-35/27) + 7
X = (- 157/27 +7 ) /4
2007-06-16 15:44:22 · answer #2 · answered by buoisang 4 · 0⤊ 0⤋
-4x + 5y = - 14
4x + 16y = - 28-----ADD
21y = - 42
y = - 2
x - 8 = - 7
x = 1
SOLUTION: x = 1 , y = - 2
2007-06-16 18:36:42 · answer #3 · answered by Como 7 · 0⤊ 0⤋