If the discriminant of a quadratic equation is equal to -8, there are two complex roots.
<h3>Discriminant of a quadratic equation</h3>
The discriminant is used to determine the nature of quadratic equations.
The formula for calculating discriminant is given as:
D = b^2 - 4ac
If the discriminant is negative, it means that the nature of the solution will be a complex number.
Hence if the discriminant of a quadratic equation is equal to -8, there are two complex roots.
Learn more on discriminant here: brainly.com/question/2507588
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1. It is fairly tedious to use construction techniques on paper to rotate a figure 90°, and somewhat error-prone to use a protractor. So, the attached makes use of a geometry program to rotate the parallel lines. In each case, XE is rotated to X'E.
d) You notice the resulting lines A'B' and C'D' are both perpendicular to the original AB and CD and are parallel to each other. They are the same distance apart that they were. (Rotation does not change distances or angles.)
2.
a) ∠ABC is supplementary to ∠CBD, so has measure 180°-50° = 130°.
b) ∠EBD is a vertical angle to ∠ABC, so has the same measure, 130°.
c) ∠ABE is a vertical angle to ∠DBC, so has the same measure, 50°.
The perimeter is the sum of all sides' lengths
So the perimeter = 4*160 m =640 m = 0.64 km