Given is square root of a negative real number, i.e.
When we find square root of positive real numbers, we get Real answers.
But when we find square root of negative real numbers, we get Imaginary answers. To solve them, we can split the given negative number into product of -1 and the number itself but with positive sign. e.g. -4 = -1 x 4.
For square root of -1, we use english letter 'i' called Imaginary unit i.e. 
Now we can use -0.25 = -1 x 0.25

Hence, "0.5i" is the final answer.
Answer:
B. x = -5 +/- √30.
Step-by-step explanation:
2x^2 + 20x = 10
2(x^2 + 10x) = 10
2[ (x + 5)^2 - 25 ] =10
2(x + 5)^2 - 50 = 10
2(x + 5)^2 = 60
(x + 5)^2 = 30
x + 5 = +/- √30
x = -5 +/- √30.
It would be the same as moving the decimal three to the right, and that applies to everything, not just the metric system.
There are an infinite number of such subsets. One of them is the set of real numbers in the interval (7, 8). Perhaps you're thinking "irrational" numbers, as opposed to "integers" or "rational" numbers.
Answer:
Domain: {-4, -2, 0, 2, 4}
Range: {-2, -1, 0 1, 2}
Step-by-step explanation: