We can use substitution.
We can substitute 2x + 3 for 'y' in the 2nd equation.
y = 3x + 5
2x + 3 = 3x + 5
Subtract 3 to both sides:
2x = 3x + 2
Subtract 3x to both sides:
-x = 2
Multiply -1 to both sides:
x = -2
Now we can plug this into any of the two equations to get our y-value:
y = 2x + 3
y = 2(-2) + 3
y = -4 + 3
y = -1
So our solution is (-2, -1)
For number 30, its easier if its broken down so were going to make it √200*x^2*y^2*z^2. We can't get a square root of 200 so we will break it into 100*2 to get √2*100*x^2*y^2*z^2. Now let's look at what we can take the square roots of. 2 doesn't have a nice sq. rt. so we will leave it there. 100 has the rt. of 10 so we can make 10√2*x^2*y^2*z^2. X^2 has the root x and we can follow this with the other variables to get 10xyz√2. There is your final simplified answer.
Answer:
The number of tickets they need to sell is 
Step-by-step explanation:
The formula is p = n(d - c), where
- P is the total profit made from the event
- n is the number tickets sold
- d is the price charged for each dinner
- c is the cost of food per plate
To find the number of tickets they need to sell separate n in one side and the other variables p, d and c in the other side
p = n(d - c)
n is multiplied by the difference of d and c, so lets divide both sides by the difference of d and c

Cancel (D_C) up with (d - c) down in the right hand side

Switch the two side

The number of tickets they need to sell is 