Question : If $a-b=2$ and $ab=15$, then what is the value of $a^3-b^3$?

Option 1: 152

Option 2: 112

Option 3: 108

Option 4: 98

Question : If a³ + b³ = 152 and a + b = 8, then what is the value of ab?

Option 1: 2

Option 2: 11

Option 3: –10

Option 4: 15

Question : If $a + b = 6$ and $ab = 5$, then what is the value of $a^3 + b^3$?

Option 1: 106

Option 2: 136

Option 3: 126

Option 4: 116

Question : If $a+\frac{1}{a}=5$, then what is the value of $a^3+\frac{1}{a^3} ?$

Option 1: 110

Option 2: 15

Option 3: 105

Option 4: –10

Question : $\frac{1}{\sqrt a}-\frac{1}{\sqrt b}=0$, then the value of $\frac{1}{a}+\frac{1}{ b}$ is:

Option 1: $\frac{1}{\sqrt{ab}}$

Option 2: $\sqrt{ab}$

Option 3: $\frac{2}{\sqrt{ab}}$

Option 4: $\frac{1}{2\sqrt{ab}}$

Question : If $\frac{2+a}{a}+\frac{2+b}{b}+\frac{2+c}{c}=4$, then the value of $\frac{ab+bc+ca}{abc}$ is:

Option 1: $2$

Option 2: $1$

Option 3: $0$

Option 4: $\frac{1}{2}$