Question 726720
2x^2-3xy+2y(y+1)=3x+13
x-y=3 --> y = x-3
Sub for y in the 1st eqn'
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2x^2-3x(x-3) +2(x-3)*(x-2) = 3x+13
{{{2x^2 - 3x^2 + 9x + 2x^2 - 10x + 12 = 3x+13}}}
{{{x^2 - x + 12 = 3x+13}}}
{{{x^2 - 4x - 1 = 0}}}
*[invoke solve_quadratic_equation 1,-4,-1]
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x = sqrt(5) + 2, y = sqrt(5) - 1
x =~ 4.236, y = 1.236
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x = 2 - sqrt(5), y = -1 - sqrt(5)
x =~ -0.236, y = -3.236