Step by step
The question
Question: solve for h in A = (a + b)h/2.
We treat the other letters like numbers.
1 h on the left
h is on the right.
We swap the two sides, so h is on the left.
They are still equal.
2 Remove the fraction
There is a fraction: over 2.
Times 2 removes it.
We do it on both sides.
2/2 is 1.
The fraction is gone.
Now we have (a + b)h = 2A.
3 Remove the (a + b)
(a + b)h means (a + b) times h.
We want just h.
To remove times (a + b), we divide by (a + b).
We do it on both sides.
(a + b) divided by (a + b) is 1.
So just h is left.
So h = 2A/(a + b).
4 Check
Let's check with numbers.
We pick A = 3, a = 2, b = 4.
Our answer gives h = 1.
Now we put all the numbers into the start.
First the left side.
Now the right side.
Both sides are 3.
So our answer is right!
Let's look back.
First: h on the left.
Then: remove the fraction.
Then: remove the (a + b).
Last: check.