Answer :
The solution to the given equation is x = 1, y = 2, z = 3. That is (1, 2, 3)
System of Linear Equations
From the question, we are to solve the given system of linear equations
The given system of linear equation is
x + 2y - z = 2 ----------- (1)
2x - 7y + 5z = 3 ----------- (2)
-4x + y + 2z = 4 ----------- (3)
From equations (1) and (2), eliminate z
5 × ( x + 2y - z = 2
1 × ( 2x - 7y + 5z = 3
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5x + 10y -5z = 10
2x -7y + 5z = 3
Add the resulting equations
7x + 3y = 13 ----------- (4)
From equations (2) and (3), eliminate z
2 × ( 2x - 7y + 5z = 3
5 × ( -4x + y + 2z = 4
-----------------------------------
4x - 14y + 10z = 6
-20x + 5y + 10z = 20
Subtract the resulting equations
24x - 19y = -14 ---------- (5)
Now, solve equations (4) and (5) simultaneously
7x + 3y = 13
24x - 19y = -14
Eliminate y
19 × ( 7x + 3y = 13
3 × ( 24x - 19y = -14
---------------------------------
133x + 57y = 247
72x - 57y = -42
Add the resulting equations
205x = 205
x = 205/205
x = 1
Substitute the value of x into equation (4)
7x + 3y = 13
7(1) + 3y = 13
7 + 3y = 13
3y = 13 - 7
3y = 6
c = 6/3
y = 2
Substitute the values of x and y into equation (1)
x + 2y - z = 2
1 + 2(2) - z = 2
1 + 4 - z = 2
1 + 4 - 2 = z
3 = z
z =3
The solution to the given equation is x = 1, y = 2, z = 3. That is (1, 2, 3)
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