How do you multiply $(1) / (y^2 - 4) = (1) / (y + 2)$ ?

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Answer 1 · 2015-05-21T03:25:11

$(1) / (y^2 - 4) = (1) / (y + 2)$

We know that $color(blue)(a^2 - b^2 = (a+b)(a-b)$

so,
$(y^2 - 4) = (y+2)(y-2)$
rewriting the expression:

$(1) / ((y+2)(y-2)) = (1) / (y + 2)$

$(1) / cancel((y+2)(y-2)) = (1 . (y-2))/ cancel((y + 2)(y-2)$

$1 = y-2$

$y =1+2 = 3$

How do you multiply (1) / (y^2 - 4) = (1) / (y + 2)(1) / (y^2 - 4) = (1) / (y + 2)?