Well, we need to know how much was money the individual started with.
Answer:
20
Step-by-step explanation:
You need to create two equations for each company and then set them equal to each other. The keywords base fee means you will pay this amount regardless, so this amount stays constant and it will be the constant in the equation. The other keyword is per. Per will link the variable with the coefficient.
The first equation for company M:
y = 12x + 60
The second equation for company N:
y = 9x + 120
Set the equations equal to each other.
9x + 120 = 12x + 60
Solve for x. I am going to subtract 9x from both sides first.
9x - 9x + 120 = 12x -9x +60
120 = 3x +60
Now, I will subtract 60 from both sides.
120 - 60 = 3x + 60 - 60
60 = 3x
Finally, I will divide both sides by 3
60/3 = 3x/3
x = 20
20 is how many guests it will take for the total cost to be the same.
Multiply both numerator and denominator of 
by the complex conjugate of the denominator, -2+9i.
Multiplication can be transformed into difference of squares using the rule: 
.
By definition, i² is -1. Calculate the denominator.
Multiply complex numbers 5-3i and -2+9i in the same way as you multiply binomials.
Do the multiplications in 
.
Combine the real and imaginary parts in -10+45i+6i+27.
Do the additions in 
.
Divide 17+51i by 85 to get 
.
The real part of 
is 
.
