Question

Consider the given system of linear equations. 2x+y-z=8 x+4y+z=7 -3x+2y-3z=21

Answer 1

The system of equations has the solution:

x = 111/42

y = 27/14

z = -15/6

How to solve the system of linear equations?

We start with 3 linear equations:

2x+y-z=8

x+4y+z=7

-3x+2y-3z=21

To solve this, first we need to isolate one of the variables. I will isolate x on the second one:

x = 7 - 4y - z

Now we can replace that in the other two:

2*( 7 - 4y - z) + y - z = 8

-3*(7 - 4y - z) + 2y - 3z = 21

Now we need to isolate other variable, let's isolate y on the above one:

14 - 8y - 2z + y - z = 8

-7y - 3z = 8 - 14 = -6

z = (-6 + 7y)/-3 = 2 - (7/3)*y

Now we replace this on the last equation:

-21 + 12y -3z + 2y - 3z = 21

14y - 6z = 42

14y - 6*(2 - (7/3)*y) = 42

14y - 12 + 14y = 42

28y = 42 + 12 = 54

y = 54/28 = 27/14

Now that we know the value of y, we can find the value of z:

z = 2 - (7/3)*y = 2 - (7/3)*27/14 = 2 - 27/6 = -15/6

And the value of x:

x = 7 - 4y - z = 7 - 4*(27/14) + 15/6 = 7 - 48/7 + 15/6 = 111/42

So the solution is:

x = 111/42

y = 27/14

z = -15/6

If you want to learn more about systems of equations:

brainly.com/question/13729904

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