Question

Q.19 please help to this question
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Answer 1

.....

...............

Answer 2

a^2+b^2

2+1+4/2+1-4+1/a^2

7/-1+1/a^2

7a^2+1/-a^2=0

7a^2+1=0

7a^2=-1

a^2=-1/7

a= 1/root 7