How do you factor $p^{2} - 19 p - 42 = 0$ $p^2- 19p - 42 = 0$ ?

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Answer 1 · 2016-05-26T16:36:07

You only asked for the factorisation!

$(p + 2) (p - 21) = 0$ $(p+2)(p-21)=0$
$p = - 2 and/or p = + 21$ $p=-2" and/or "p=+21$

Notice that $2 \times 21 = 42 and - 21 + 2 = - 19$ $2xx21=42" and "-21+2=-19$

So we have:

$(p + 2) (p - 21) = 0$ $(p+2)(p-21)=0$

Thus for the above to be true $p$ $p$ has to have one of the two solutions:

$p = - 2 and/or p = + 21$ $p=-2" and/or "p=+21$

How do you factor p^2- 19p - 42 = 0p2−19p−42=0p^2- 19p - 42 = 0?