What is the sum of square root of - 2 and square root of - 18?

Sqrt - 2 = i sqrt2

sqrt - 18 = 3i sqrt2

Add these up

√-2 + √-18

√-2 = √ (-1*2) = √-1 * √2 = i√2 Recall square root of - 1 = i

√-18 = √ (-1*18) = √-1 * √1'8 = i√18 Recall square root of - 1 = i

But √18 = √ (9*2) = √9 * √2 = 3√2

√-18 = i√18 = i (3√2) = 3i√2

√-2 + √-18 = i√2 + 3i√2 = (i + 3i) √2 = 4i√2

So the sum is 4i√2, where i = √-1

Hope this explains it.