If x= -1
so.
2(-1)^2-5 / (-1 +9)
=-3/8
=-0.375
If they sell for $5/pound and you have 20 pounds, that means you'll gain $100 if you sell all of it. So, in order to not go in debt you need you either spend less money than $100 or $100 exactly.
We can make a system of equations to help solve for how many pounds of each we should get:
8x + 3y = 100
x + y = 20
First we want to solve for x in one of the equations:
x = 20 - y
Then we plug that value into the other equation:
8(20 - y) + 3y = 100
Now we simplify everything
160 - 8y + 3y = 100
160 - 5y = 100
Minus 160 on both sides
-5y = 100 - 160
Divide by negative 5 to solve for y
-5y = -60
y = 12
So now we know that we should get 12 pounds of the $3 chocolates. We need 8 more pounds of the $8 chocolates to have a total of 20 pounds.
20 - 12 = 8
Place value is where the number is placed and value is what that place is called