The two equations are:
The easiest way is to eliminate one of the unknowns by rearranging (2) so that y can be expressed as function of x, substituting this into (1) which will give a quadratic involving only x which can then be solved. (Alternatively rearranging 2 to express x in terms of y and then substituting for x in (1) can be done, but this leads to fractions which are not so easy to work with.) Once the values of x have been found, equation (2) can be used to find the corresponding values of y.
Rearranging (2) to make y the subject gives y = 1 -2x
Substituting this for y in (1) gives:
x² - x(1 - 2x) - (1 - 2x)² = -11
→ x² - x + 2x² - (1 - 4x + 4x²) = -11
→ 3x² - x - 1 + 4x - 4x² = -11
→ -x² + 3x - 1 = -11
→ x² - 3x - 10 = 0
→ (x - 5)(x + 2) = 0
→ x = 5 or -2
Using (2) this gives:
x = 5 → y = 1 - 2×5 = -9
x = -2 → y = 1 - 2×-2 = 5
→ The solutions are the points (5, -9) and (-2, 5)
The solutions are: x = 4, y = 2 and x = -4, y = -2
They are: (3, 1) and (-11/5, -8/5)
1st equation: x^2 -xy -y squared = -11 2nd equation: 2x+y = 1 Combining the the two equations together gives: -x^2 +3x +10 = 0 Solving the above quadratic equation: x = 5 or x = -2 Solutions by substitution: (5, -9) and (-2, 5)
These are two expressions, not equations. Expressions do not have solutions, only equations do. NB equations include the equals sign.
Four.
The solutions are: x = 4, y = 2 and x = -4, y = -2
They are: (3, 1) and (-11/5, -8/5)
If: 2x+y = 5 and x2-y2 = 3 Then the solutions work out as: (2, 1) and ( 14/3, -13/3)
1st equation: x^2 -xy -y squared = -11 2nd equation: 2x+y = 1 Combining the the two equations together gives: -x^2 +3x +10 = 0 Solving the above quadratic equation: x = 5 or x = -2 Solutions by substitution: (5, -9) and (-2, 5)
These are two expressions, not equations. Expressions do not have solutions, only equations do. NB equations include the equals sign.
The two rational solutions are (0,0,0) and (1,1,1). There are no other real solutions.
Four.
4
Merge the equations together and form a quadratic equation in terms of x:- 3x2-20x+28 = 0 (3x-14)(x-2) = 0 x = 14/3 or x = 2 So when x = 14/3 then y = -13/3 and when x = 2 then y = 1
If: x = 2y-2 and x^2 = y^2+7 Then: (2y-2)^2 = y^2+7 So: (2y-2)(2y-2) = y^2+7 It follows: 4y^2-y^2-8y+4-7 = 0 => 3y^2-8y-3 = 0 Solving the above quadratic equation: y = -1/3 or y = 3 Solutions: when y = 3 then x = 4 and when y = -1/3 then x = -8/3
If you mean: x2+2x+1 = 0 then it is a quadratiic equations whose solutions are equal because x = -1 and x = -1
If: x = 2y-2 and x^2 = y^2+7 Then: (2y-2)^2 = y^2+7 => 4y^2-8y+4 = y^2+7 => 3y^2-8y-3= 0 Solving the above quadratic equation: y = -1/3 or y = 3 Solutions by substitution: when y=-1/3 then x=-8/3 and when y=3 then x=4