The product of Shikha's age five years ago and her age 8 years later is 30,

Let the present age of Shikha be $x$ years

Then, 8 years later, age of her $=(x+8)$ years

Five years ago, her age $=(x-5)$ years

Then according to question,

$(x-5)(x+8)=30$

$x^{2}+8 x-5 x-40=30$

$x^{2}+3 x-40-30=0$

$x^{2}+3 x-70=0$

$x^{2}+3 x-70=0$

$x^{2}-7 x+10 x-70=0$

$x(x-7)+10(x-7)=0$

$(x-7)(x+10)=0$

So, either 

$(x-7)=0$

$x=7$

Or

$(x+10)=0$

$x=-10$

But the age never be negative

Hence, the present age of Shikha be $=7$ years