How do you solve $-2n^2 - 8n + 19 = -3n^2 + 4$ ?

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Answer 1 · 2018-05-12T09:38:34

$n=5, n=3$

$-2n^2 - 8n + 19 = -3n^2 + 4$

Subtract 4 from both sides.
$-2n^2 -8n + 19 - 4 = -3n^2 cancel(+4 - 4)$

$rArr -2n^2 - 8n +15 = -3n^2$

Add 3n^2 to both sides.

$-2n^2 - 8n + 15 + 3n^2 = cancel(-3n^2 + 3n^2)$

$rArr n^2 -8n + 15 = 0$

Factorise (if possible), if not complete the square or use the quadratic formula.

$(n-5)(n-3)$

Set equal to $0$ :

$n-5=0$

$n=5$

$n-3=0$

$n=3$

How do you solve -2n^2 - 8n + 19 = -3n^2 + 4-2n^2 - 8n + 19 = -3n^2 + 4?