You can add 4/9.
A simple trick is to look at the numerator and denominator separately, if they're both perfect squares then you're good (4, 2^2, check. 9, 3^2, check.)
This is simply a question about ratios. This ratio means that for every 1 cm on the map, there are 12 km in actuality. You can set this problem up in fractions:
1 cm 12 cm
-------- = ----------
12 km x
To solve for x, we cross-multiply, for the moment ignoring units. Remember, your answer will be in km.
1*x=12*12
x=144
If x=144, then for 12 cm, there are 144 km.
5(n-4)=(4n-12)
First: Distribute 5 into n and -4.
5(n-4)=(5n)+(5*-4)= 5n-20.
Second: Subtract 4n from both sides to eliminate the variable from the right side of the equation.
(5n-20)=(4n-12)
n-20=-12
Next: Add 20 to both sides to eliminate the constant from the left side of the equation.
n-20=-12
n=8
The unknown number is 8.
Answer:
Step-by-step explanation:
Solve for 
:
-Multiply both sides of the equation by the denominator 
:
-Subtract both sides by 
:
So, the value of is 
.
