To solve equations like this we need to do inverse operations.
First we need to build an equation: 9+3x=21
We pass the nine to the other side, subtracting the 9 to 21, that leaves us with 3x=12
After that we just divide 12 by 3, wich gives us x=4, or, as it says in the question: n=4
Now let's double check:
N=4, since 3*4=12 and 12+9=21
Hope it is helpful :)
Answer:
2
Step-by-step explanation:
He made 1 full one and the other contained 5
Answer:
111 spots
Step-by-step explanation:
Let y denote the total number of parking spots expressed as:
Given that x is the number of spots in the first row.
-Now, given that the first row has 32 spots, we substitute in the expression to solve for y:
Hence, there are 111 spots in the parking lot.
We have
x² + 24x = 17 (1)
Note that
(x + 12)² = x² + 24x + 144
By adding 144 to the left side of equation (1), it becomes a perfect square.
Therefore
x² + 24x = (x+12)² - 144 (2)
Substitute (2) into (1).
(x + 12)² - 144 = 17
(x + 12)² = 17 +144
(x + 12)² = 161
Answer:
We added 144 to the left side of equation (1) in order to make it a perfect square.