Express as product: First, we express −72 as the product of square roots and −1.−72=−1×72=−1×72
Simplify 72: Next, we simplify 72 by finding the largest square factor of 72. The largest square factor of 72 is 36, which is 62. So we can write 72 as 36×2. 72 = 36×2 = 720721722 = 723
Express as i: Now, we express −1 as the imaginary unit i.−1=i
Combine results: Finally, we combine the results from the previous steps to write −72 in simplest radical form as a complex number.−72= −1⋅72= i⋅6⋅2= −720⋅2= −723
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