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if-a-b-a-b-23-then-faind-a-b-




Question Number 131525 by mathlove last updated on 05/Feb/21
 if   (a−b)(a+b)=23  then  faind   a∙b=?
if(ab)(a+b)=23thenfaindab=?
Answered by mr W last updated on 05/Feb/21
no unique solution for a,b∈R.  for a,b∈Z:  (a−b)(a+b)=23=1×23  ⇒a−b=1  ⇒a+b=23  ⇒a=((1+23)/2)=12  ⇒b=((23−1)/2)=11  ⇒a×b=12×11=131  or  a−b=−1  a+b=−23  ⇒a=−12  ⇒b=−11  ⇒a×b=131
nouniquesolutionfora,bR.fora,bZ:(ab)(a+b)=23=1×23ab=1a+b=23a=1+232=12b=2312=11a×b=12×11=131orab=1a+b=23a=12b=11a×b=131
Commented by mathlove last updated on 05/Feb/21
thanks
thanks
Commented by Rasheed.Sindhi last updated on 06/Feb/21
Also possible:  a+b=1 ∧ a−b=23       a=12,b=−11       a.b=−132              OR  a+b=−1 ∧ a−b=−23       a=−12,b=11       a.b=−132
Alsopossible:a+b=1ab=23a=12,b=11a.b=132ORa+b=1ab=23a=12,b=11a.b=132
Commented by mr W last updated on 06/Feb/21
correct sir! thanks for remark!
correctsir!thanksforremark!

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