10.0k views
2 votes
Determine the values of a for which the system has no solutions, exactly one solution, or infinitely many solutions. x + 2y + z = 2, 2x - 2y + 3z = 1, x + 2y - (a2 - 3)z = a

1 Answer

5 votes

Answer:

a) If
2-a^(2)=0 and
a-2\\eq 0. The system has no solution

b) If
2-a^(2)\\eq 0 and a different to 2, we have a unique solution.

c) If
2-a^(2)=0 and
a-2=0 we have infinitely solutions.

Explanation:

We need to rewrite the third equation in terms of a and z to solve this.

Let's start solving the first equation:


x+2y+z=2 (1)

If we subtract z in both side of this equation we will have:


x+2y=2-z (2)

Now we can put the equation 2 into the last equation:


x+2y-(a^(2)-3)z=a


2-z-(a^(2)-3)z=a (3)

Simplifying the equation 3 we have:


z(2-a^(2))=a-2 (4)

Now we can analyzes the equation 4 for each case:

a) If
2-a^(2)=0 and
a-2\\eq 0. The system has no solution

b) If
2-a^(2)\\eq 0 and a different to 2, we have a unique solution.

c) If
2-a^(2)=0 and
a-2=0 we have infinitely solutions.

I hope it helps you!

User Agregoire
by
6.5k points