Solve for b. A=1/2(b+h)

            b = 2A - h

Step-by-step explanation:

A = 1/2(b+h)

×2      ×2

2A = b + h

- h       - h

2A - h = b

b = 2A - h

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.

Looks pretty good to me!