Math Problem Statement

solve 3y+ x= 3 and xy=5 simultaneously

Solution

To solve the system of equations simultaneously:

  1. 3y+x=33y + x = 3
  2. xy=5xy = 5

Step 1: Solve one equation for one variable.

From equation (1), solve for xx in terms of yy:

x=33yx = 3 - 3y

Step 2: Substitute into the second equation.

Now substitute this expression for xx into equation (2):

(33y)y=5(3 - 3y)y = 5

Step 3: Simplify the equation.

Distribute yy on the left-hand side:

3y3y2=53y - 3y^2 = 5

Rearrange the equation to form a quadratic equation:

3y23y+5=03y^2 - 3y + 5 = 0

Step 4: Solve the quadratic equation.

The quadratic equation is 3y23y+5=03y^2 - 3y + 5 = 0. To solve this, use the quadratic formula:

y=b±b24ac2ay = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

Here, a=3a = 3, b=3b = -3, and c=5c = 5. Substitute these into the quadratic formula:

y=(3)±(3)24(3)(5)2(3)y = \frac{-(-3) \pm \sqrt{(-3)^2 - 4(3)(5)}}{2(3)}

Simplify:

y=3±9606y = \frac{3 \pm \sqrt{9 - 60}}{6} y=3±516y = \frac{3 \pm \sqrt{-51}}{6}

Since the discriminant is negative (51-51), the solutions for yy are complex:

y=3±i516y = \frac{3 \pm i\sqrt{51}}{6} y=12±i516y = \frac{1}{2} \pm \frac{i\sqrt{51}}{6}

Step 5: Find xx.

Now, substitute these values of yy back into x=33yx = 3 - 3y to find the corresponding xx values. Since the solutions for yy are complex, the solutions for xx will also be complex.

For y=12+i516y = \frac{1}{2} + \frac{i\sqrt{51}}{6}:

x=33(12+i516)x = 3 - 3\left(\frac{1}{2} + \frac{i\sqrt{51}}{6}\right) x=332i512x = 3 - \frac{3}{2} - \frac{i\sqrt{51}}{2} x=32i512x = \frac{3}{2} - \frac{i\sqrt{51}}{2}

For y=12i516y = \frac{1}{2} - \frac{i\sqrt{51}}{6}:

x=33(12i516)x = 3 - 3\left(\frac{1}{2} - \frac{i\sqrt{51}}{6}\right) x=32+i512x = \frac{3}{2} + \frac{i\sqrt{51}}{2}

Final solutions:

The solutions are:

x=32±i512,y=12±i516x = \frac{3}{2} \pm \frac{i\sqrt{51}}{2}, \quad y = \frac{1}{2} \pm \frac{i\sqrt{51}}{6}

These are complex solutions.

Would you like more details on any step or have any questions?


Here are 5 questions to expand this topic:

  1. How do you handle systems of equations when both equations are quadratic?
  2. What are real-world applications of complex numbers in solving equations?
  3. How can the quadratic formula be derived?
  4. What does the discriminant tell you about the nature of solutions?
  5. How can simultaneous equations be solved graphically?

Tip: The discriminant b24acb^2 - 4ac reveals whether the solutions are real or complex, and whether they are distinct or repeated.

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Math Problem Analysis

Mathematical Concepts

Algebra
Simultaneous Equations
Quadratic Equations
Complex Numbers

Formulas

Quadratic Formula: y = (-b ± √(b² - 4ac)) / 2a
Linear Equation Solution: x = 3 - 3y

Theorems

Quadratic Formula
Discriminant

Suitable Grade Level

Grades 10-12