If a2 - b2 = 8 and a*b = 2, find a4 + b4.
If a2 - b2 = 8 and a*b = 2, find a4 + b4.
Answer/Solution
72
Steps/Work
a2 - b2 = 8 : given
a4 + b4 - 2a2b2 = 82 : square both sides and expand.
a*b = 2 : given
a2b2 = 22 : square both sides.
a4 + b4 - 2(4) = 82 : substitute
a4 + b4 = 72
correct answer B
a4 + b4 - 2a2b2 = 82 : square both sides and expand.
a*b = 2 : given
a2b2 = 22 : square both sides.
a4 + b4 - 2(4) = 82 : substitute
a4 + b4 = 72
correct answer B