How do you factor the expression $y^2 +6y - 16$ ?

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Answer 1 · 2016-03-14T19:35:32

$y^2+6y-16 = (y+8)(y-2)$

Note that in general:

$(y+a)(y-b) = y^2+(a-b)y-ab$

So we want to find a pair of factors $a$ and $b$ of $16$ which differ by $6$ .

The pair $8, 2$ works in that $8-2=6$ and $8*2 = 16$ .

Hence:

$y^2+6y-16 = (y+8)(y-2)$

How do you factor the expression y^2 +6y - 16y^2 +6y - 16?