So you know that 1 cubic foot is equal to 80 pounds. So, the first point would be (1,80).
You can find the other points by multiply 80 by a number, and when I did that, I got (2,160) and (3,240) too.
I hope this helps :)
The correct answer will be 5z^3
We can put the two equations together with substitution, and we get
3x + 2y = 30
Now we have a single equation in two variables, so we don't have enough information to solve for both x and y.
X=23 First, you have to subtract 12 by 12 to cancel it out. Next, you have to do the same thing to 20.05. 20.05 minus 12 is 8.05. All you have left is .35x. To get rid of the this you have to divide .35x by .35. Now all you have left is x. Finally you have to do the same thing to 8.05. 8.05 divided by .35 is 23. So, x=23