How do you solve $7x^2+10x=2x^2+155$ using any method?

Question

1443 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-08-12T20:08:09

$x=4sqrt2-1$ or $x=4sqrt2+1$

$7x^2+10x=2x^2+155$

$hArr7x^2+10x-2x^2-155=0$ or

$5x^2+10x-155=0$ and dividing by $5$

$x^2+2x-31=0$

and using quadratic formula $(-b+-sqrt(b^2-4ac))/2a$ , as we have here $a=1$ , $b=2$ and $c=-31$

$x=(-2+-sqrt((-2)^2-4×1×(-31)))/(2×1)$ or

$x=(-2+-sqrt(4+124))/(2×1)$ or

$x=(-2+-sqrt128)/2$ or

$x=(-2+-8sqrt2)/2=-1+-4sqrt2$ or

$x=4sqrt2-1$ or $x=4sqrt2+1$

How do you solve 7x^2+10x=2x^2+1557x^2+10x=2x^2+155 using any method?