Question

Solve the following system of equations.

x + 3y – z = 2
x – 2y + 3z = 7
x + 2y – 5z = –21

A. (–2, 3, 5)
B. (2, 3, –5)
C. (2, –3, 5)
D. (2, 3, 5)

Answer 1

A

Answer 2

sav u must do it for ur self

Answer 3

i honestly don't know how.

Answer 4

i know you can

Answer 5

you can try solving by substitution

Answer 6

or try this, eq 1 mult by 3 to cancel out z, by adding eq 2 and eq1

x + 3y – z = 2 eq (1) mult by 3 to get 3x + 9y -3z = 6
x – 2y + 3z = 7 eq(2) +(x – 2y + 3z = 7)
x + 2y – 5z = –21 eq (3) --------------------
4x+7y+0=13 eq 4
mult eq1 by 5 then subtract to eq3
5x+15y-5z= 10
-(x + 2y – 5z = –21) eq (3)
--------------
4x+13y+0 =31 eq5 subtract this to eq 4
-(4x+7y+0=13) eq 4
---------------
0 +6y =18
y=18/6=3 ans now sub this to eq(4 or 5)
4x+7y+0=13 eq 4
4x+7(3)+0=13 eq 4
x=-2 ans then sub x=-2 and y=3 to eq1
x + 3y – z = 2
-2 + 3(3) – z = 2
z=5 ans therefore (x,y,z)=(-2,3,5) answer