For this case we must find an expression equivalent to:
![x ^ 3 * y ^ {- 7}](https://tex.z-dn.net/?f=x%20%5E%203%20%2A%20y%20%5E%20%7B-%207%7D)
By definition of power properties we have to meet:
![a ^ {-1} = \frac {1} {a ^ 1} = \frac {1} {a}](https://tex.z-dn.net/?f=a%20%5E%20%7B-1%7D%20%3D%20%5Cfrac%20%7B1%7D%20%7Ba%20%5E%201%7D%20%3D%20%5Cfrac%20%7B1%7D%20%7Ba%7D)
Then, we can rewrite the expression as:
![x ^ 3 * \frac {1} {y ^ 7} =\\\frac {x ^ 3} {y ^ 7}](https://tex.z-dn.net/?f=x%20%5E%203%20%2A%20%5Cfrac%20%7B1%7D%20%7By%20%5E%207%7D%20%3D%5C%5C%5Cfrac%20%7Bx%20%5E%203%7D%20%7By%20%5E%207%7D)
Answer:
![\frac {x ^ 3} {y ^ 7}](https://tex.z-dn.net/?f=%5Cfrac%20%7Bx%20%5E%203%7D%20%7By%20%5E%207%7D)
Equate the expressions for m.
7x = 3x + 20
4x = 20 . . . . . . . subtract 3x
x = 20/4 = 5 . . . divide by 4
The value of x is 5.
There are 27 bricks in the 12th row. Hope this helps ! :)
Answer:
3
Step-by-step explanation: