Question

showthat(7×+9y) ²-252 xy =(7×-9y)²​

Answer 1

Answer:

-4 x 7

Step-by-step explanation:

I hope this will help you with

(7×+9y) ²-252 xy =(7×-9y)²

Answer 2

${\huge{\underline{\boxed{\red{\mathcal{Answer}}}}}}$

To Prove:

• (7x + 9y)² - 252xy = (7x - 9y)²

Proof:

Taking LHS,

➡ (7x + 9y)² - 252xy

➡ [(7x)² + 2(7x)(9y) + (9y)²] - 252xy

➡ (7x)² + 126xy + (9y)² - 252xy

➡ (7x)² + 126xy - 252xy + (9y)²

➡ (7x)² - 126xy + (9y)²

➡ (7x)² - 2(7x)(9y) + (9y)²

➡ (7x - 9y)² = RHS

Hence Proved.

Formulae Used:

• (a+b)² = a² + 2ab + b²
• a² - 2ab + b² = (a-b)²

Learn More:

$\boxed{\begin{minipage}{7 cm}\boxed{\bigstar\:\:\textbf{\textsf{Algebric\:Identity}}\:\bigstar}\\\\1)\bf\:(A+B)^{2} = A^{2} + 2AB + B^{2}\\\\2)\bf\: (A-B)^{2} = A^{2} - 2AB + B^{2}\\\\3)\bf\: A^{2} - B^{2} = (A+B)(A-B)\\\\4)\bf\: (A+B)^{2} = (A-B)^{2} + 4AB\\\\5)\bf\: (A-B)^{2} = (A+B)^{2} - 4AB\\\\6)\bf\: (A+B)^{3} = A^{3} + 3AB(A+B) + B^{3}\\\\7)\bf\:(A-B)^{3} = A^{3} - 3AB(A-B) - B^{3}\\\\8)\bf\: A^{3} + B^{3} = (A+B)(A^{2} - AB + B^{2})\\\\9)\bf\: A^{3} - B^{3} = (A-B)(A^{2} + AB + B^{2})\\\\ \end{minipage}}$