Question

Use the substitution method to solve the following system of equations.

x + 2y – z = 2
3x + y – 2z = –15
3x + 4y – 3z = –2

Answer 1

Eq. 1: x + 2y - z = 2
z = x + 2y - 2
Substitute into Eq. 2
3x + y - 2(x + 2y - 2) = -15
x - 3y + 4 = -15
x = 3y - 19
Substitute values for x and z into Eq. 3
3(3y - 19) + 4y - 3((3y - 19) + 2y - 2) = -2
9y - 57 + 4y - 15y + 63 = -2
-2y + 6 = -2
2y = 8
y = 4
And then you repeat the whole process again. A bit tedious but it's just manipulating algebraic equations...

Answer 2

thank you.