Question

Expand (2a+b-3c) square​

Answer 1

Answer:

$4a^{2}$ + 4ab - 12ac + $b^{2}$ - 6bc + $9c^{2}$

Hope it helps

Answer 2

Answer- The above question is from the chapter 'Polynomials'.

Polynomial- It is an algebraic expression involving use of variables and constants.

p(x)- It is used to denote a polynomial. It is read is 'Polynomial in x'.

Important identities:

1) (a+b)² = a² + 2ab + b²

2) (a-b)² = a² - 2ab + b²

3) (a+b)(a-b) = a² - b²

4) (a+b+c)² = a² + b² + c² + 2ab + 2bc + 2ac

Concept used: (a+b+c)² = a² + b² + c² + 2ab + 2bc + 2ac

Given question: Expand (2a + b - 3c)².

Solution:  (2a + b - 3c)²

= [2a + b + (-3c)]²

Now, using the identity of (A + B + C)² where A = 2a, B = b and C = -3c, we get,

= (2a)² + (b)² + (-3c)² + 2 × 2a × b + 2 × b × -3c + 2 × -3c × 2a

= 4a² + b² + 9c² + 4ab - 6bc - 12ac

∴ The value of (2a + b - 3c)² = 4a² + b² + 9c² + 4ab - 6bc - 12ac.