Expanding (2a-3b)^2
The expression (2a-3b)^2 represents the square of the binomial (2a-3b). To expand it, we can use the FOIL method or the square of a binomial formula.
FOIL Method
FOIL stands for First, Outer, Inner, Last. It helps us multiply each term of the first binomial by each term of the second binomial:
- First: (2a * 2a) = 4a^2
- Outer: (2a * -3b) = -6ab
- Inner: (-3b * 2a) = -6ab
- Last: (-3b * -3b) = 9b^2
Adding all the terms together, we get: 4a^2 - 6ab - 6ab + 9b^2
Simplifying the expression, we get:
** (2a-3b)^2 = 4a^2 - 12ab + 9b^2 **
Square of a Binomial Formula
The square of a binomial formula is a shortcut for expanding expressions like (2a-3b)^2:
(a-b)^2 = a^2 - 2ab + b^2
Applying this formula to our expression:
- a = 2a
- b = 3b
Substituting the values in the formula:
(2a - 3b)^2 = (2a)^2 - 2(2a)(3b) + (3b)^2
Simplifying the expression, we get:
(2a-3b)^2 = 4a^2 - 12ab + 9b^2
Conclusion
Both methods lead to the same result: (2a-3b)^2 = 4a^2 - 12ab + 9b^2. The choice of method depends on personal preference and the complexity of the expression.