Which of the following statement is correct ?
I. If x = 12, y = -2 and z = -10, then $x^3 + Y^3 +z^3 = 360$.
II. If x + y = 48 and 4xy = 128, then $ 4x^2 +4y^2 = 4480$.
Answer & explanation
Correct answer: option 1
I. If x = 12, y = -2 and z = -10, then $x^3 + Y^3 +z^3 = 360$.
= $12^3 + -2^3 +-10^3 = 720$.(Not true)
II. If x + y = 48 and 4xy = 128, then $ 4x^2 +4y^2 = 4480$
= 4x2 +4y2 = 4( x2 + y2 ) = 4 ( 482 - 2 × 32 ) = 8960 Not true
Neither I nor II