Let's try to simplify x^2 + 16. It's a sum of two squares:
x^2 + 16 = 0
x^2 = -16
The problem is, we can't take a square root of a negative. This is where imaginary numbers come in.
Remember that square roots have a plus or minus symbol outside:
±√-16 = ±4i
Our two roots are 4i and -4i. Therefore, the trinomial simplifies to:
(x + 4i)(x - 4i)
If we attempt to divide x + 4 by these two binomials, we will find that 4 and 4i are not like terms. Therefore, we can't simplify this expression.
Answer:

Step-by-step explanation:
For this case we want to find this probability:

Because they want the area to the left of the value. We need to remember that the normal standard distribution have a mean of 0 and a deviation of 1.
We can use the following excel code: =NORM.DIST(-1.55,0,1,TRUE)
And we got:

The other possibility is use the normal standard table and we got a similar result.
Answer:
1 and - 1
Step-by-step explanation:
The equation of a line passing through the origin is
y = mx ( m is the slope ( gradient ) )
y = x ← is in this form
with gradient m = 1
Parallel lines have equal gradients
Then the gradients of lines parallel to the given line is 1
Given a line with gradient m then the gradient of a line perpendicular to it is
= -
= -
= - 1
Then the gradients of lines perpendicular to this line is - 1