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+11 votes
1k views

How many solutions does the following system of linear equations have?

$-x + 5y = -1$

$x - y = 2$

$x + 3y = 3$

  1. infinitely many
  2. two distinct solutions
  3. unique
  4. none
asked in Linear Algebra by Veteran (59.5k points) | 1k views

3 Answers

+15 votes
Best answer
answer = C

rank = r(A) = r(A|B) = 2

rank = total number of variables
Hence, unique solution
answered by Boss (30.7k points)
selected by
0
Number of free variables=n-r=2-2=0, so no infinite, only unique solutions.
+13 votes
C unique solution..
3 equation , 2 variable.
solve any two equation and check 3rd equation by putting values in 3rd equation.
x = 9/4 , y = 1/4
answered by Veteran (55.1k points)
+2 votes

DIFFERENT APPROACH

all the equations are linearly independent. i.e non of the equations can be obtained by multiplying one of equation with a number (this means that no two vectors overlap each other leading to a rank of 3). therefore there will be a unique solution. 

Correct me if wrong :)

answered by Junior (911 points)


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