<span>They must sell 1200 yearbooks to break even hope this helped</span>
X= cost per cherry pie
y= cost per pumpkin pie
NICOLE
1x + 9y= $60
LISA
11x + 4y= $90
STEP 1
multiply Nicole's equation by -11
-11(1x + 9y)= -11($60)
multiply -11 by all terms
(-11 * x) + (-11 * 9y)= (-11 * 60)
-11x - 99y= -660
STEP 2
add Nicole's new equation from step 1 to Lisa's equation to solve for y (using the elimination method)
-11x - 99y= -660
11x + 4y= 90
the x terms "cancel out"
-95y= -570
divide both sides by -95
y= $6 per pumpkin pie
STEP 3
substitute y value into either original equation to solve for x
x + 9y= $60
x + 9(6)= 60
x + 54= 60
subtract 54 from both sides
x= $6 per cherry pie
CHECK
11x + 4y= $90
11(6) + 4(6)= 90
66 + 24= 90
90= 90
ANSWER: Each cherry pie costs $6 and each pumpkin pie costs $6.
Hope this helps! :)
There are two ways to work this out: normal variables or using "imaginary" numbers.
Normal variables:
![(7+2i)(3-i)\\(7*3)+[7*(-i)]+(3*2i)+[2i*(-i)]\\21-7i+6i-2i^{2}\\\\21-i-2i^{2}](https://tex.z-dn.net/?f=%20%287%2B2i%29%283-i%29%5C%5C%287%2A3%29%2B%5B7%2A%28-i%29%5D%2B%283%2A2i%29%2B%5B2i%2A%28-i%29%5D%5C%5C21-7i%2B6i-2i%5E%7B2%7D%5C%5C%5C%5C21-i-2i%5E%7B2%7D)
Imaginary numbers:
Using the result from earlier:

Now since

, then the expression becomes:
Answer:
C. 120 students
Step-by-step explanation:
10 + 15 + 20 +30 = 75%
100 - 75 = 25%
25% chose football which is 100 students
30% chose swimming
setup proportion:
25/100 = 30/x
25x = 100(30)
25x = 3000
x = 120