Solve the following system of equations: 3x² + 4xy - 2y² = 2 3x + 2y = -10 Solve the second equation for either of the unknowns. I'll pick x: 3x + 2y = -10 add -2y to both sides 3x = -10 - 2y Divide both sides by 3 x = (-10 - 2y)/3 factor out -2 x = -2(5 + y)/3 In the first original equation, 3x² + 4xy - 2y² = 2 substitute -2(5 + y)/3 for x 3[-2(5 + y)/3]² + 4[-2(5 + y)/3]y - 2y² = 2 3[4(5 + y)²/9] + 4y[-2(5 + y)/3] - 2y² = 2 4(5 + y)²/3 - 8y(5 + y)/3 - 2y² = 2 4(25 + 10y + y²)/3 - (40y + 8y²)/3 - 2y² = 2 Multiply through by 3 to clear of fractions: 4(25 + 10y + y²) - (40y + 8y²) - 6y² = 6 100 + 40y + 4y² - 40y - 8y² - 6y² = 6 Collect terms 100 - 10y² = 6 Get 0 on the right 94 - 10y² = 0 Divide thru by 2 47 - 5y² = 0 -5y² = -47 y² = 47/5 ____ y = ±Ö47/5 ___ Rationalize denominator y = ±Ö235/5 Substitute into 3x + 2y = -10 Using the + value ___ 3x + 2(Ö235/5) = -10 Multiply through by 5 ___ 15x + 2Ö235 = -50 ___ 15x = -50 - 2Ö235 ___ x = (-50 - 2Ö235)/15 ___ x = -2(25 + Ö235)/15 So one solution is ___ ___ (x, y) = ( -2(25 + Ö235)/15, Ö235/5 ) ---------------------------------------- Using the - value ___ 3x + 2(-Ö235/5) = -10 Multiply through by 5 ___ 15x - 2Ö235 = -50 ___ 15x = -50 + 2Ö235 ___ x = (-50 + 2Ö235)/15 ___ x = -2(25 - Ö235)/15 So the other solution is ___ ___ (x, y) = ( -2(25 - Ö235)/15, -Ö235/5 ) Tell your teacher I said he or she is a meany for giving you such a messy problem. It is messy enough as it is. However, if you solve for y first instead of x, the problem is even messier, in fact a lot messier. That was the first way I did it!! Also there is no way to tell in advance which way is going to be messier. Your teacher needs a spanking!! :-) Edwin