Solving quadratic equations:

What is the value of "b" in the triangle where one part of the right angle is "3b" and the other part of the right angle is "b". The area inside is 24 in^2.

Please solve and explain. Thanks

3b/2 * b = 24 In^2

Multiply both sides by 2:
3b * b = 48
3b^2 = 48
b^2 = 16.
b = +-4 In.