Question

if C(a^2-a,2)=C(a^2-a,4),. then a=

Answer 1

' Hola User_________________

Here is YOUR Answer...!!!
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↪⭐Actually welcome to the concept of the P AND C ....

↪Since tho property used is ....

↪nCp = nCr

↪then always p+ r = n

↪so after solving we get as ....

↪a^2 - a - 6 =0

↪solving this quadratic equation we get as ...

↪〽⭐a = 3
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⭐⭐⭐〽〽〽〽⭐⭐⭐⭐⭐

Answer 2

Answer:   3

Step-by-step explanation:

$^{(a^2-a)}C_2=^{(a^2-a)}C_4\\\;\\We\;know\;that\\\;\\if,\;\;^nC_r=^nC_p\implies\;r+p=n\\\;\\Therefore,\\\;\\2+4=a^2-a\\\;\\6=a^2-a\\\;\\a^2-a-6=0\\\;\\a^2+2a-3a-6=0\\\;\\a(a+2)-3(a+2)=0\\\;\\(a-3)(a+2)\\\;\\\textbf{Hence,}\\\;\\a=3$