If a - b = 7 and
a2 + b2 = 85,
then the value of ab is:
Answer & explanation
Correct answer: option 4
Given,
a - b = 7
a2 + b2 = 85
( a - b )2 = a2 + b2 - 2ab
49 = 85 - 2ab
ab = 18
If a - b = 7 and
a2 + b2 = 85,
then the value of ab is:
Correct answer: option 4
Given,
a - b = 7
a2 + b2 = 85
( a - b )2 = a2 + b2 - 2ab
49 = 85 - 2ab
ab = 18