First add up the total of the food. Then, multiply it by .2 (20%), and subtract that number from your total. You will get the price Jeff paid for his food.
Answer:
7-9
Step-by-step explanation:
Sebastian goes up from 0 by 7 floors. Then, he goes down by 9.
I am going to explain this using the substitution method, considering it appears to be the best in this situation.
We know (from the bottom equation) that y can equal 3x+20. Using this knowledge, we substitute the y in the top equation for 3x+20. Now, we have an equation that looks like this:
3x+20=x^2+2x
Now we need to move x to one side and then do some radicals (square roots).
Subtract the 2x on the right (since it is smaller, negatives = NONONO), which will give you
x+20=x^2
Now, we take the square root of both sides to get
rad(x+20)=x
Now we have to simplify. 20 doesn't have a square root, but 4 goes into 20, and 4 has a square root of 2. This now becomes
2rad(x+5)
This doesn't simplify any further... we have a problem... no way to isolate x as far as my knowledge goes... Sorry, can't help you any further than that, but another person or your teacher might be able to. R.I.P...
Answer:
231
Step-by-step explanation:
=
42÷2= 21
9×21= 189
189 students total
42 6th graders
Let
x--------------> total volume of a glass
we know that
(4/7)x-70=(2/4)x------------> (4/7)x-70=(1/2)x--------> 2*(4/7)x-2*70=x
(8/7)x-140=x
<span>multiplied by 7 the expresion
</span>7*(8/7)x-7*140=7*x-----------> 8x-980=7x--------> x=980 cm³
the answer is
<span>the total volume of the glass is 980 cm</span>³