Jambmaths question:
A binary operation * is defined by a* b =ab, If a * 2 =2 – a. Find the possible value of a
Option A:
1, –2
Option B:
1, 2
Option C:
2, –2
Option D:
1, –1
Jamb Maths Solution:
$\begin{align} & a*2={{a}^{2}}-----(i) \\ & a*2=2-a----(ii) \\ & {{a}^{2}}=2-a \\ & {{a}^{2}}+a-2=0 \\ & (a+2)(a-1)=0 \\ & a=-2\text{ or }a=1 \\\end{align}$
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