Question

factorise : 9(x + y)² - 16 (x - 2y)²​

Answer 1

Step-by-step explanation:

hope the answer may help u

Answer 2

Answer:

9(x+y)²-16(x-2y)².

(x+y)².

It is in the form of (a+b)²=a²+2ab+b² where a=x & b=y.

(x+y)²=(x)²+2(x)(y)+(y)².

=x²+2xy+y².

(x-2y)².

It is in the form of (a-b)²=a²-2ab+b² where a=x &9 b=2y.

(x-2y)²=(x)²-2(x)(2y)+(2y)².

=x²-4xy+4y².

9(x+y)²-16(x-2y)²=9(x²+2xy+y²)-16(x²-4xy+4y²).

=9x²+18xy+9y²-16x²+64xy-64y². (Because -×-=+ & -×+=-).

=9x²-16x²+18xy+64xy+9y²-64y². (Because by combining like terms to avoid confusion).

=-7x²+82xy-55y². (Because +×-=- & largest number is important).

(or).

Divide equation by -.

=-7x²+84xy-55y².

___ ____ ____

- - -

=7x²-84xy+55y². (Because -÷-=+ & +÷-=-).

I think this is your answer.