The first thing to do is to convert the negative so that we can find the square root of 144

`therefore sqrt(-144) = sqrt(-1 times 144)`

As `sqrt(-1) = i`

`therefore sqrt(-144) = isqrt(144)`

144 is a square number (12 x 12)

`therefore = i sqrt(12 times 12)` Note:`sqrt(12 times 12) = 12`

`therefore = 12 i`

**Ans: The square root of -144 = 12i**

Let number be x ,whose square be -144 i.e.

`x^2=-144=-1xx144=i^2xx144` ,where `i^2=-1`

`x^2=i^2xx2xx2xx2xx2xx3xx3`

`x=sqrt(i^2xx2xx2xx2xx2xx3xx3)`

`x=+-ixx2xx2xx3`

`x=+-i12`

Since it is negative, there will be an i in the answer. 144 is a perfect square for 12. Therefore the answer is -12.

the square root of 144 is 12 but because it is -144 the 12 will have to be a complex number therefore imaginary.

so `sqrt(-144)=12i`