Question : If $(x-5)^2+(y-2)^2+(z-9)^2=0$, then value of $(x+y-z)$ is:

Option 1: 16

Option 2: –1

Option 3: –2

Option 4: 12

Question : If $\frac{(x+y)}{z}=2$, then what is the value of $[\frac{y}{(y-z)}+\frac{x}{(x-z)}]?$

Option 1: $0$

Option 2: $1$

Option 3: $2$

Option 4: $–1$

Question : If $4x–7y=3$ and $2x–y=9$, then the value of $(x–y)$ is:

Option 1: 3

Option 2: 4

Option 3: 5

Option 4: 6

Question : If $x+y+z=0$ and $x^2+y^2+z^2=40$, then what is the value of $x y+y z+z x?$

Option 1: –20

Option 2: 5

Option 3: –5

Option 4: –10

Question : If $x + y = 1$, then what is the value of $x^3+ 3xy + y^3$?

Option 1: –1

Option 2: 1

Option 3: 0

Option 4: 2