If a + b = 5 and ab = 13, then what will be the value of $$\text{a}^3+\text{b}^3$$​ ?

Correct option is D

Given: 

a + b = 5

ab = 13 

Formula Used: 

​$$a^3+b^3 = (a+b)(a^2−ab+b^2)$$ 

​$$a ^2 +b ^2 =(a+b) ^2 −2ab$$​​

Solution:  

$$a ^2 +b ^2 =25 −2(13)=25−26=−1$$​

$$a ^3 +b ^3 =5(−1−13)\\ \ \\=5(−14)=−70$$​​