Question 919862

Solve the system by elimination or substitution.
3y^2=xy
2x^2+xy-84=0
<pre>
Solve the system by elimination or substitution.
{{{3y^2 = xy}}}______{{{x = 3y^2/y}}}______{{{x = 3y}}} ------ eq (i)
{{{2x^2 + xy - 84 = 0}}} ------ eq (ii)
{{{2(3y)^2 + y(3y) - 84 = 0}}} -------- Substituting 3y for x in eq (ii)
{{{2(9y^2) + 3y^2 - 84 = 0}}}
{{{18y^2 + 3y^2 - 84 = 0}}}
{{{21y^2 - 84 = 0}}}
{{{21(y^2 - 4) = 21(0)}}}
{{{y^2 - 4 = 0}}}_____{{{y = 0 +-sqrt(4)}}}________{{{highlight_green(y = 0+-2)}}}
{{{x = 3(2)}}} -------- Substituting 2 for y in eq (i)
{{{highlight_green(x = 6)}}}
{{{highlight_green(highlight_green(system(x = 6_when,y = 2)))}}}

{{{x = 3(- 2)}}} ------ Substituting - 2 for y in eq (i)
{{{highlight_green(x = - 6)}}}
{{{highlight_green(highlight_green(system(x = - 6_when,y = - 2)))}}}