Evaluate: sqrt(-49)

Expression: $\sqrt{ -49 }$

Write the number as a product with the factor $-1$

$\sqrt{ 49 \times \left( -1 \right) }$

The root of a product is equal to the product of the roots of each factor

$\sqrt{ 49 }\sqrt{ -1 }$

Write the number in exponential form with the base of $7$

$\sqrt{ {7}^{2} }\sqrt{ -1 }$

Use $\sqrt[2]{-1}=i$ to simplify the expression

$\sqrt{ {7}^{2} }i$

Reduce the index of the radical and exponent with $2$

$7i$