Engineering
Mathematics
Solving System of Linear Equation Cramers Rule
Question

Let a, λ, m ∈ R. Consider the system of linear equations

ax + 2y = λ

3x – 2y = μ

Which of the following statement(s) is(are) correct?

If λ + μ = 0, then the system has infinitely many solutions for a = – 3.

If a ≠ – 3, then the system has a unique solution for all values of λ and μ.

If λ + μ ≠ 0, then the system has no solution for a = – 3.

If a = – 3, then the system has infinitely many solutions for all values of λ and μ.

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Solution

            ax + 2y = λ

           3x – 2y = µ

(i)         If a1a2=b1b2=c1c2  the infinite solution

           ∴a3=−1=λµ

            ⇒         a = –3 & λ = –µ

            ⇒         λ + µ = 0

(ii)         If a1a2≠b1b2  then unique solution

            a3≠ –1             ⇒ a ≠ –3

(iii)        If a1a2=b1b2≠c1c2  then no solution

            a = –3 and λ + µ ¹ 0.

            ∴         no solution

            ∴         BCD. Ans.