LIC AAO Model Paper 4

I. ${\left(\mathit{x}+\mathit{y}\right)}^3$ = 1331
⇒ x + y = 11
⇒ y = 11 - x
From equation III,
x (11 -x) = 28
⇒ 11x - ${\mathit{x}}^2$ = 28
⇒ ${\mathit{x}}^2$ - 11x + 28 = 0
⇒ ${\mathit{x}}^2$ - 7x - 4x + 28 = 0
⇒ x (x - 7) - 4 (x - 7) = 0
⇒ (x - 7) (x - 4) = 0
⇒ x = 7 , 4
From equation I
y = 4, 7
From equation II
7-4 + z = 0
⇒ z = -3
4-7 +-z = 0
r z = 3