If ^ (a^2-a) C_ 2 =^ (a^2-a) C_ 4 , is then x: 1. 2 2. 3 3. 4 4. … - Vidyadip

Question

If $^{(\text{a}^2-\text{a})}\text{C}_{\text{2}}=^{(\text{a}^2-\text{a})\text{}}\text{C}_{\text{4}},$ is then x:

2
3
4
None of these

✓

Answer

3

Solution:

$\text{a}^{2}-\text{a}=2+4$

$\Rightarrow \text{a}^{2}-\text{a}-6=0$

$\Rightarrow \text{a}^{2}-3\text{a}+2\text{a}-6=0$

$\Rightarrow \text{a}(\text{a}-3)+2(\text{a}-3)=0$

$\Rightarrow (\text{a}+2)(\text{a}-3)=0$

$\Rightarrow \text{a}=-2,\text{a}=3$

$\text{a}=3$

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