Answer:
xy = -7/2
Explanation:
Given the system of equation;
x +y +z = 2 ......1
2x + 3y - z = -3 .....2
3x + y + z = 4....3
Add 1 and 2;
x+2x + y + 3y = 2-3
3x + 4y = -1 ..... 4
Add 2 and 3
2x+3x + 3y + y = -3+4
4x + 4y = 1 ..... 5
Equate 4 and 5 and solve;
3x + 4y = -1 ..... 4
4x + 4y = 1 ..... 5
Subtract
3x - 4x = -1-1
-x = -2
x = 2
substitute x - 2 into 4;
From 4; 3x+4y = -1
3(2) +4y = -1
6 + 4y = -1
4y = -1-6
4y = -7
y = 7/-4
y = -7/4
Product of x and y = 2 * -7/4 = -7/2