Question

(A+B) 2 =A 2 +B 2 +2AB-2AB That is right.

Answer 1

No it is wrong
(A+B)^2 = A^2 + B^2 + 2AB

Answer 2

Answer -

This is the formula to Solve Algebra expressions.

Correct Formula -

$\displaystyle \mathsf{(a+b)^2 = a^2 +2ab+b^2}$

Proof -

We have,

$\sf\\ \\\implies (a+b)^2 = (a+b)(a+b)$

Now,

$\sf\\ \\\implies a(a+b)+b(a+b)$

$\sf\\ \\\implies a^2 +ab+ba+b^2$

$\sf\\ \\\implies a^2 +2ab+b^2$

Note -

$\displaystyle \mathsf{\because ba = ab}$

Hence, We get this -

$\displaystyle \mathsf{(a+b)^2 = a^2 +2ab+b^2}$

$\rule{300}{1.5}$

Example -

Question -

• (3p + 2) = ?

Solution -

Given -

(3p + 2) = ?

Formula to be used -

$\displaystyle \mathsf{(a+b)^2 = a^2 +2ab+b^2}$

Values in Equation,

$\sf\\ \\\implies (3p+2)^2 = (3p)^2 + 2\times 3p\times2+(2)^2$

$\sf\\ \\\implies (3p+2)^2 = 9p^2 + 12p + 4$

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