solve this system?

0 ⤊

x - 3y =15
4x + y =8

2x - y = 22
-x + 3y = -15

2007-08-08 11:45:30 · 2 answers · asked by luicanna 1 in Science & Mathematics ➔ Mathematics

2 answers

x - 3y =15
4x + y =8 --------------*3
12x+3y=24
x - 3y =15
---------------------------add
13x=39
x=39/13=3

4*3+y=8
y=8-12=-4

2007-08-08 11:51:57 · answer #1 · answered by Anonymous · 0⤊ 0⤋

x - 3y =15 <-- Eq 1
4x + y =8 <-- Eq2
Multiply Eq 2 by 3 getting 12x+3y=24, add to Eq1 getting:
13x = 39 --> x=3
So 4*3 +y = 8 --> y = -4

2x - y = 22
-x + 3y = -15 <-- Multiply by 2 and add to 1st equation getting
5y = -8 --> y = - 8/5 = - 1.6
2x+1.6 =22
2x = 20.4 --> x = 10.2

2007-08-08 18:58:14 · answer #2 · answered by ironduke8159 7 · 0⤊ 0⤋