Question : If $3x+5y+7z=49$ and $9x+8y+21z=126,$ then what is the value of $y$?

Option 1: 4

Option 2: 2

Option 3: 3

Option 4: 5

Question : If $ \frac{(5x\:-\:y)}{(5x\:+\:y)}=\frac{3}{7},$ what is the value of $\frac{(4x^{2}\:+\:y^{2}\:–\:4xy)}{(9x^{2}\:+\:16y^{2}\:+\:24xy)}$?

Option 1: $0$

Option 2: $\frac{3}{7}$

Option 3: $\frac{18}{49}$

Option 4: $\frac{1}{6}$

Question : If $x+ \frac{1}{9x}=4$, then the value of $9x^2+ \frac{1}{9x^2}$ is:

Option 1: 140

Option 2: 142

Option 3: 144

Option 4: 146

Question : If $9x^2+16y^2=60$ and $3x+4y=6$, then the value of $xy$ is:

Option 1: –1

Option 2: 1

Option 3: –2

Option 4: 2

Question : If $x+y+z=0$, then what is the value of $\frac{x^2}{3z}+\frac{y^3}{3xz}+\frac{z^2}{3x}$?

Option 1: $0$

Option 2: $xz$

Option 3: $y$

Option 4: $3y$

Question : If $2x-5y=5$ and $2x-y=9$, then $(x-y)$ is equal to:

Option 1: 2

Option 2: 4

Option 3: 6

Option 4: 3