Question 678397
FOIL
{4x)(3x) + 4x(40) + 12(3x) + 12(40) = 180
{{{12x^2 + 160x + 36x + 480 = 180}}}
Combine like terms
{{{12x^2 + 196x + 480 - 180 = 0}}}
{{{12x^2 + 196x + 300 = 0}}}
Divde the entire equation by 12
{{{x^2 + 49/3 + 25 = 0}}}
Quadtratic Formula
x = {{{(-196 +- sqrt(196^2-4(12)(300)))/2(12)}}}
x = {{{(-196 +- sqrt(38416-14400))/24}}}
x = {{{(-196 +- sqrt(24016))/24}}}
x = {{{(-196 +- sqrt(16*1501))/24}}}
x = {{{(-196 +- 4sqrt(1501))/24}}}
x = {{{(-49cross(-196)+- cross(4)sqrt(1501))/(6cross(24))}}}
...
{{{highlight_green(x=(-49+sqrt(1501))/6)}}}
AND
{{{highlight_green(x=(-49-sqrt(1501))/6)}}}
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