2x+3y= -16 at the bottom will be
5x-10y=20
2007-05-17 17:21:07 · 6 answers · asked by Lucia O 1 in Science & Mathematics ➔ Mathematics
Divide the second equation by 5
x - 2y =4
x = 4+2y
sub
2(4+2y) +3y = -16
8 +4y + 3y = -16
7y = -24
y = -24/7
x= 4+2y
x = 4 + 2(-24/7)
x = 4 - 48/7
x = -20/7
(-20/7,-24/7)
2007-05-17 17:37:59 · answer #1 · answered by lizzie 3 · 0⤊ 0⤋
This problem can be done in 2 ways, the easiest, in my opinion being elimination method. When doing these types of problems, you must think to yourself, "How can I cancel out one variable?" One simple way in this problem to get rid of a variable would be to multiply both sides of the first equation by 2.5.
2.5*(2x + 3y) = 2.5* (-16) Note: It is okay to multiply an equation as long as you multiply both sides by the same amount.
Perfoming this operation we get:
5x + 7.5y = -40
The second equation is 5x -10 y =20. So lets subtract one equation from the other.
5x + 7.5y = -40
- 5x - 10y =20 =
17.5y = -60
Now that this problem is down to one variable we can solve for y:
y = -60/17.5
Now solving for x we can substitute y into any equation we feel like:
2007-05-18 00:40:11 · answer #2 · answered by Matthew K 2 · 0⤊ 0⤋
x=-20 y=8
2007-05-18 00:29:11 · answer #3 · answered by pranav 2 · 0⤊ 0⤋
-5(2x+3y= -16 )
2(5x-10y=20)
-10X-15y+10x-20y=120
-35y=120
y= - 60/7
then solve for x
2007-05-18 00:31:19 · answer #4 · answered by Anonymous · 0⤊ 0⤋
20x + 30y = - 160
15x - 30y = 60-------ADD
35x = - 100
x = - 100 / 35 = - 20 / 7
- 40/7 + 3y = - 16
3y = - 112/7 + 40/7
3y = - 72 / 7
y = - 24 / 7
x = - 20/7 , y = - 24 / 7
2007-05-18 13:41:06 · answer #5 · answered by Como 7 · 0⤊ 0⤋
1) First make addition
2x +3y = -16
+5x -10y = 20
___________
7x -7y = 4
2) Make subtraction
2x +3y = -16
-5x -10y = 20
___+____-____
-3x+13y = -26
2007-05-18 06:40:24 · answer #6 · answered by Archu 2 · 0⤊ 0⤋