Practicing Success
Which of the following statement is correct? I. If x = 12, y = -2 and z = -10, then $x^3+y^3+z^3=720$ II. If x + y = 48 and 4xy = 128, then s the value of $4x^2 +4y^2 is 8960$ |
Neither I nor II Only I Both I and II Only II |
Both I and II |
I. If x = 12, y = -2 and z = -10, then $x^3+y^3+z^3=720$ $x^3+y^3+z^3$ = 123 + (-2)3 + (-10)3 $x^3+y^3+z^3$ = 1728 - 8 - 1000 = 720 II. If x + y = 48 and 4xy = 128, then s the value of $4x^2 +4y^2 is 8960$ $x^3+y^3$ = 4 ( x2 + y2 ) = 4 (x2 + y2 + 2xy) xy = \(\frac{128}{4}\) = 32 482 = ( x2 + y2 + 2 × 32 ) x2 + y2 = 2240 4 ( x2 + y2 ) = 4 × 2240 = 8960 Both I and II |