Answer:
80+100 equal 180
Step-by-step explanation:
because if u add 80+100 equal 180
You use a system of equations
x= coffee
y= donuts
x+y=100
3x+y=180
there’s 3 ways to solve system of equations substitution graphing and elimination. it would be easiest to use substitution here. So you multiply x+y=100 by -1 so it become -x-y=-100. then you combine it with the other equation and get 2x=80 so x=40 which means 40 cups of coffee were sold then you plug it back in to find y. 40+y=100. y=60.
y= 60 (donuts). x= 40 (coffee)
i am completely confused how is this even physically possible what the heck
The answer is The 3rd one
The idea here is to combine the equations into one in only one variable. The last equation is in only x and z so lets sub out y in the second.
-x - y - z = -8
8 - x - z = y
Substitute y with (8 - x - z) into the next equation.
-4x + 4(8 - x - z) + 5z = 7
-4x + 32 - 4x - 4z + 5z = 7
-8x + 32 + z = 7
The variable z is easiest to get alone; use that as substitution in the last equation.
z = 7 + 8x - 32
z = 8x - 25
Substitute z with (8x - 25)
2x + 2(8x - 25) = 4
2x + 16x - 50 = 4
18x = 4 + 50
18x = 54
x = 3
So use x = 3 in that last equation to find z.
2(3) + 2z = 4
6 + 2z = 4
2z = 4 - 6
2z = -2
z = -1
Now, use both x = 3 and z = -1 to find the final variable y.
-3 - y - (-1) = -8
-3 - y + 1 = -8
-2 - y = -8
-y = -8 + 2
-y = -6
y = 6
Solutions x,y,z = ( 3, 6, -1)
