Question

What is the solution to the following system { -4y=8, x+3y-3z=-26, 2x-5y+z=19

Answer 1

Solution of given system is x =-4, y = -5, z = 5.

Answer 2

-4y = 8
y = 8/-4
y = -2

x + 3y - 3z = -26
x + 3(-2) - 3z = -26
x - 6 - 3z = -26
x - 3z = -20

2x - 5y + z = 19
2x - 5(-2) + z = 19
2x + 10 + z = 19
2x + z = 9

x - 3z = -20....multiply by -2
2x + z = 9
--------------
-2x + 6z = 40 (result of multiplying by -2)
2x + z = 9
--------------add
7z = 49
z = 49/7
z = 7

2x + z = 9
2x + 7 = 9
2x = 9 - 7
2x = 2
x = 1

so x = 1, y = -2, and z = 7 <==