.If p^2+q^2= 5 and pq =2 find p^3-q^3
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Answer:
p^3-q^3=±7
Step-by-step explanation:
pq=2
p=2/q
p^2+q^2=5 (substitute p)
(2/q)^2+q^2=5
4/q^2+q^2=5 (multiply all by q^2)
4+q^4=5q^2
q^4-5q^2+4=0
(q^2-4)(q^2-1)=0
q=2, q=1
q=2 then p=2/q p=1
q=1 then p=2/q p=2
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