2x-y=4
Therefore: y=2x-4
---------------------------------
5x-10/4(2x-4)=10
5x-5/2(2x-4)=10
5x-5x+10=10
10=10
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*Problem can't be solved.
Let x be the length and y be the width.
We know already

Area of the base

Area of the sides:

We get the equation

We will solve the system:

The above system has no real solution, please check your values.
Answer:
59070
Step-by-step explanation:
The answer is 9, because you subtract 21 from 30 and you get 9. When you add 21+9 you get 30.