Question

if a+b=5 and ab=9/4. then (a^3)+(b^3)
??​

Answer 1

Answer:

see answer in above picture

Step-by-step explanation:

use formula and you will get answer

Answer 2

Step-by-step explanation:

=> a + b = 5

Cubing on both sides

=> $(a+b)^3 = 5^3$

=> $a^3+b^3+3ab(a+b)=125$

=> $a^3+b^3+3(\frac{9}{4})(5)=125$

=> $a^3+b^3 = 125 - \frac{285}{4}$

=> $a^3+b^3=\frac{500-285}{4} = \frac{215}{4}$

Therefore , $a^3+b^3 = 53.75$