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Mathematics
Mathematics
Problem
Let
λ
\lambda
λ
be a real number for which the system of linear equations
x
+
y
+
z
=
6
x + y + z = 6
x
+
y
+
z
=
6
,
4
x
+
λ
y
−
λ
z
=
λ
−
2
4x + \lambda y - \lambda z = \lambda - 2
4
x
+
λ
y
−
λ
z
=
λ
−
2
,
3
x
+
2
y
−
4
z
=
−
5
3x + 2y - 4z = -5
3
x
+
2
y
−
4
z
=
−
5
has infinitely many solutions. Then
λ
\lambda
λ
is a root of the quadratic equation. (1)
λ
2
−
3
λ
−
4
=
0
\lambda^2 - 3\lambda - 4 = 0
λ
2
−
3
λ
−
4
=
0
(2)
λ
2
−
λ
−
6
=
0
\lambda^2 - \lambda - 6 = 0
λ
2
−
λ
−
6
=
0
(3)
λ
2
+
3
λ
−
4
=
0
\lambda^2 + 3\lambda - 4 = 0
λ
2
+
3
λ
−
4
=
0
(4)
λ
2
+
λ
−
6
=
0
\lambda^2 + \lambda - 6 = 0
λ
2
+
λ
−
6
=
0
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