Math Problem Statement

Solve the simultaneous equations: y = x + 3 and x^2 + y^2 = 5.

Solution

Let's analyze the problem in the image you uploaded. You have a system of two equations:

  1. y=x+3y = x + 3
  2. x2+y2=5x^2 + y^2 = 5

a) Show that x2+3x+2=0x^2 + 3x + 2 = 0

To do this, we will substitute the expression for yy from the first equation into the second equation.

Start with the first equation: y=x+3y = x + 3 Substitute y=x+3y = x + 3 into the second equation: x2+(x+3)2=5x^2 + (x + 3)^2 = 5

Expand (x+3)2(x + 3)^2: x2+(x2+6x+9)=5x^2 + (x^2 + 6x + 9) = 5

Simplify the equation: x2+x2+6x+9=5x^2 + x^2 + 6x + 9 = 5 2x2+6x+9=52x^2 + 6x + 9 = 5 Now subtract 5 from both sides: 2x2+6x+4=02x^2 + 6x + 4 = 0 Divide the entire equation by 2 to simplify: x2+3x+2=0x^2 + 3x + 2 = 0 Thus, we have shown that x2+3x+2=0x^2 + 3x + 2 = 0.

b) Solve the simultaneous equations

To solve for xx and yy, we now solve the quadratic equation x2+3x+2=0x^2 + 3x + 2 = 0.

Factor the quadratic equation: (x+1)(x+2)=0(x + 1)(x + 2) = 0 Set each factor equal to zero: x+1=0orx+2=0x + 1 = 0 \quad \text{or} \quad x + 2 = 0 Solving these gives: x=1orx=2x = -1 \quad \text{or} \quad x = -2

Now, substitute these values of xx into the first equation y=x+3y = x + 3 to find the corresponding values of yy.

For x=1x = -1: y=1+3=2y = -1 + 3 = 2

For x=2x = -2: y=2+3=1y = -2 + 3 = 1

Thus, the solutions are:

  1. (x,y)=(1,2)(x, y) = (-1, 2)
  2. (x,y)=(2,1)(x, y) = (-2, 1)

Final Answer:

  • The solutions are (1,2)(-1, 2) and (2,1)(-2, 1).

Would you like more detailed steps or have any questions about this process?


Here are some related questions:

  1. How do you solve a quadratic equation using the quadratic formula?
  2. What happens if you have a system of equations with no solutions?
  3. How do you verify that a pair of values satisfies both equations in a system?
  4. What are the properties of a system of equations that can have infinitely many solutions?
  5. How do you solve for variables when they appear in both linear and quadratic equations?

Tip: Always check if the quadratic equation can be factored easily before using the quadratic formula!

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Math Problem Analysis

Mathematical Concepts

Simultaneous Equations
Quadratic Equations
Substitution Method

Formulas

Quadratic equation formula: ax^2 + bx + c = 0
Expansion of (a + b)^2 = a^2 + 2ab + b^2

Theorems

Quadratic formula

Suitable Grade Level

Grades 9-11