Answer
$12i$
Work Step by Step
Step 1: $\sqrt {-49}+\sqrt {-25}$
Step 2: $\sqrt {-1\times49}+\sqrt {-1\times25}$
Step 3: $(\sqrt {-1}\times\sqrt {49})+(\sqrt {-1}\times\sqrt {25})$
Step 4: $(i\times\sqrt {49})+(i\times\sqrt {25})$
Step 5: $(i\times7)+(i\times5)$
Step 6: $7i+5i$
Step 7: $12i$
