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24 votes
24 votes
Check whether x² +4x +4 is prefect spuare expression or not . if so factorise the expression


User Pmlarocque
by
3.0k points

1 Answer

18 votes
18 votes

Answer:

It is a perfect square expression.

It factors to (x+2)^2

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Step-by-step explanation:

The general format for a perfect square is

(a+b)^2 = a^2 + 2ab + b^2

Which can be seen through the use of the FOIL rule.

Compare x^2+4x+4 with a^2+2ab+b^2, and we have these three equivalences:

  • x^2 = a^2 .... first terms
  • 4x = 2ab .... middle terms
  • 4 = b^2 .... last terms

Since x^2 = a^2, we can apply the square root to both sides to get a = x. Similarly, 4 = b^2 leads to b = 2. We could get b = -2, but that would mean 2ab = 2x*(-2) = -4x instead of 4x. So we'll stick with b = 2 instead.

Because a = x and b = 2, we then can say:

(a+b)^2 = a^2 + 2ab + b^2

(x+2)^2 = x^2 + 2*x*2 + 2^2

(x+2)^2 = x^2 + 4x + 4

Showing that x^2+4x+4 factors to (x+2)^2.

User Cmilam
by
3.1k points
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