If a - b = 3 and
a2 + b2 = 689,
then the value of ab is:
Answer & explanation
Correct answer: option 3
Given,
a - b = 3
a2 + b2 = 689
( a - b )2 = a2 + b2 - 2ab
9 = 689 - 2ab
ab = 340
If a - b = 3 and
a2 + b2 = 689,
then the value of ab is:
Correct answer: option 3
Given,
a - b = 3
a2 + b2 = 689
( a - b )2 = a2 + b2 - 2ab
9 = 689 - 2ab
ab = 340