Answer:
x = -1 +/-2i
Step-by-step explanation:
Write the equation in standard form to find the roots, also known as the solutions, zeros, or x-intercepts, of the quadratic.
x² + 2x + 5 = 0
Use the quadratic formula by substituting a= 1, b = 2 and c = 5.

Area of one blade is
A=(1/2)b*h=(1/2)7*4=28/2=14
for four blades
14*4=56
Hm, it seems like his answer is off. The image is what I got.
The area of a traingle is

So we need to know the base and the height
To work out the sides of a right angle triangle we can use a²+b²=c
c is the hypotenuse and a and b are the other sides
Because this triangle is isoceles we know that a and b are the same
a²+b²=c²
a²+a²=c²
2a²=c²
2a²=(x√6)²
2a²=(x√6)(x√6)
2a²=x²+x√6+x√6+6
2a²=x²+x√6+x√6+6
a²=

a=

A=

A=

A=

×

×

A=

×

A=