JEE Main 2019 Mathematics question
If the system of linear equations x + y + z = 5, x + 2y + 2z = 6, x + 3y + λz = μ, (λ, μ ∈ R), has infinitely many solutions, then the value of λ + μ is:
Answer: (A)
Solution
Δ = λ − 3 = 0 and consistency gives μ = 7; λ + μ = 10.