Question

find 1. (x+y) (x+9)
2. (x+2y)²
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Answer 1

Answer:

2. (x+2y)^2 this is in the form (a+b)^2=a^2 + 2ab+b^2

So x^2 +2.x.2y+(2y)^2=x^2 +4xy+4y^2