Question

The following system is solved by substitution. Which expression is substituted for z in the second and third equations?

x + 4y + z = –10
3x – 3y + 6z = –21
x + 2y + 2z = –10

a.x + 4y – 10

b. –x + 4y – 10

c.–x – 4y – 10

d.x – 4y – 10

Answer 1

x + 4y + z = –10 -> z = –x – 4y – 10