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Last updated on September 30, 2025
In algebra, expanding expressions using formulas helps simplify calculations. One such expression is (a-b-c)², which can be expanded to simplify algebraic expressions. In this topic, we will learn the formula for (a-b-c)².
The expression (a-b-c)² can be expanded using algebraic identities. Let's learn the formula to expand (a-b-c)².
The formula for expanding (a-b-c)² is derived from the square of a trinomial. It is calculated using the formula:
(a-b-c)² = a² - 2ab - 2ac + b² + c² + 2bc
In algebra, expanding expressions like (a-b-c)² is crucial for simplifying equations and solving problems. Here are some reasons why this formula is important:
Students might find it tricky to remember the expansion formula for (a-b-c)². Here are some tips to help memorize it:
Expanding expressions like (a-b-c)² has practical applications in various fields. Here are some examples:
Students often make errors when expanding (a-b-c)². Here are some common mistakes and ways to avoid them:
Expand the expression (x-2-y)².
x² - 2x(2) - 2xy + (2)² + y² + 2(2)y
First, apply the formula (a-b-c)²: = x² - 2(x)(2) - 2(x)(y) + (2)² + y² + 2(2)(y) = x² - 4x - 2xy + 4 + y² + 4y
Expand the expression (3-a-b)².
9 - 2(3)(a) - 2(3)(b) + a² + b² + 2(a)(b)
First, apply the formula (a-b-c)²: = (3)² - 2(3)(a) - 2(3)(b) + a² + b² + 2(a)(b) = 9 - 6a - 6b + a² + b² + 2ab
Expand the expression (5-m-n)².
25 - 10m - 10n + m² + n² + 2mn
First, apply the formula (a-b-c)²: = (5)² - 2(5)(m) - 2(5)(n) + m² + n² + 2(m)(n) = 25 - 10m - 10n + m² + n² + 2mn
Jaskaran Singh Saluja is a math wizard with nearly three years of experience as a math teacher. His expertise is in algebra, so he can make algebra classes interesting by turning tricky equations into simple puzzles.
: He loves to play the quiz with kids through algebra to make kids love it.