Question : If $2^{2x-y}=16$ and $2^{x+y}=32$, the value of $xy$ is:

Option 1: $2$

Option 2: $4$

Option 3: $6$

Option 4: $8$

Question : If $\frac{3x-1}{x}+\frac{5y-1}{y}+\frac{7z-1}{z}=0$, what is the value of $\frac{1}{x}+\frac{1}{y}+\frac{1}{z}?$

Option 1: –3

Option 2: 0

Option 3: 15

Option 4: 21

Question : If $x+y+z=10$, $x y+y z+z x=25$ and $x y z=100$, then what is the value of $(x^3+y^3+z^3)$?

Option 1: 450

Option 2: 540

Option 3: 550

Option 4: 570

Question : If $x + y = 10$, $2xy = 48$ and $x > y$, then find $2x - y$.

Option 1: 6

Option 2: 8

Option 3: 4

Option 4: 3

Question : If $x^2 = y+z$, $y^2=z+x$, $z^2=x+y$, then the value of $\frac{1}{x+1}+\frac{1}{y+1}+\frac{1}{z+1}$ is:

Option 1: –1

Option 2: 1

Option 3: 2

Option 4: 4