Math Problem Statement

Solve the quadratic simultaneous equations y = 2x - 3 and x^2 + y^2 = 2.

Solution

To solve the given system of equations:

  1. y=2x3y = 2x - 3
  2. x2+y2=2x^2 + y^2 = 2

Steps:

1. Substitution:

From the first equation, substitute y=2x3y = 2x - 3 into the second equation: x2+(2x3)2=2x^2 + (2x - 3)^2 = 2

2. Expand (2x3)2(2x - 3)^2:

(2x3)2=4x212x+9(2x - 3)^2 = 4x^2 - 12x + 9 Substitute this back: x2+4x212x+9=2x^2 + 4x^2 - 12x + 9 = 2

3. Simplify:

5x212x+9=25x^2 - 12x + 9 = 2 5x212x+7=05x^2 - 12x + 7 = 0

4. Solve the quadratic equation:

Using the quadratic formula: x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} Here, a=5a = 5, b=12b = -12, and c=7c = 7: x=(12)±(12)24(5)(7)2(5)x = \frac{-(-12) \pm \sqrt{(-12)^2 - 4(5)(7)}}{2(5)} x=12±14414010x = \frac{12 \pm \sqrt{144 - 140}}{10} x=12±410x = \frac{12 \pm \sqrt{4}}{10} x=12±210x = \frac{12 \pm 2}{10}

5. Solve for xx:

x=12+210=1410=1.4x = \frac{12 + 2}{10} = \frac{14}{10} = 1.4 x=12210=1010=1x = \frac{12 - 2}{10} = \frac{10}{10} = 1

6. Find yy for each xx:

  • For x=1.4x = 1.4: y=2(1.4)3=2.83=0.2y = 2(1.4) - 3 = 2.8 - 3 = -0.2

  • For x=1x = 1: y=2(1)3=23=1y = 2(1) - 3 = 2 - 3 = -1

Solutions:

The solutions are: (x,y)=(1.4,0.2)and(x,y)=(1,1)(x, y) = (1.4, -0.2) \quad \text{and} \quad (x, y) = (1, -1)

Would you like a detailed graph or explanation of any step?

Related Questions:

  1. How do you verify the solutions graphically?
  2. How does substitution work in solving simultaneous equations?
  3. What does the quadratic formula represent geometrically?
  4. How do you check if a solution satisfies both equations?
  5. What are the possible scenarios when solving simultaneous equations (e.g., no solutions, one solution, or infinite solutions)?

Tip:

Always double-check your solutions by substituting them back into both equations.

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Math Problem Analysis

Mathematical Concepts

Simultaneous Equations
Quadratic Equations
Substitution Method

Formulas

Quadratic Formula: x = (-b ± √(b² - 4ac)) / 2a

Theorems

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Suitable Grade Level

Grade 10-12