Question 430714
#1 Substituion Method:
{{{x+y=1}}} --> y = 1-x
{{{x^2+xy-y^2=-11}}}
{{{x^2+x(1-x) - (1-x)^2=-11}}}
{{{x^2 + x - x^2 -1 + 2x - x^2 = -11}}}
{{{-x^2 + 3x -1 = -11}}}
{{{x^2 - 3x + 10 = 0}}}
(x-5)*(x+2) = 0
x = -2, y = 3 (-2,3)
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x = 5, y = -4 (5,-4)
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#2 Substituion Method:
{{{x^2+y^2=180}}}
{{{x-y=-6}}}
Similar to #1
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#3 Addition Method:
{{{2x^2+3y^2-30=0}}}
{{{5x^2-7y^2-17=0}}}
{{{10x^2 + 15y^2 = 150}}} 1st eqn x 5
{{{10x^2 - 14y^2 = 34}}} 2nd eqn x 2
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{{{29y^2 = 116}}}
{{{y^2 = 4}}}
y = +2, -2
Sub for y, find x
There are 4 intersections
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#4 Addition Method:
{{{x^2+y^2=16}}}
{{{y^2-3x=16}}}
Similar to #3, just subtract to eliminate y^2 terms