Question

$a^3+b^3=218$and$a+b=2$then the value of $\sqrt{1-ab}$

• A. 2
• B. 4
• C. 3
• D. 6

Answer 1

Answer:

D. 6

$a^3+b^3=218$and$a+b=2$

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

$2^3=218+3ab(2)$

$8-218=3ab(2)$

$-210/2=3ab$

$-105=3ab$

$-105/3=ab$

$ab=-35$

$\sqrt{1-(-35)}=\sqrt{36}$

$=6$