IDNLearn.com offers a user-friendly platform for finding and sharing answers. Our platform provides detailed and accurate responses from experts, helping you navigate any topic with confidence.

Solve the following system of equations algebraically and graphically:

[tex]\[ x + y = 4 - 3 = 0 \][/tex]
[tex]\[ x^2 - 2xy - 3 = 0 \][/tex]

Draw the graph and locate the intersection.


Sagot :

To solve the system of equations given by [tex]\(x + y - 4 = 0\)[/tex] and [tex]\(x^2 - 2xy - 3 = 0\)[/tex] algebraically and graphically, let's proceed step by step.

### Step 1: Algebraic Solution

1. Solve the first equation for [tex]\(y\)[/tex]:
[tex]\[ x + y = 4 \][/tex]
[tex]\[ y = 4 - x \][/tex]

2. Substitute [tex]\(y = 4 - x\)[/tex] into the second equation:
[tex]\[ x^2 - 2x(4 - x) - 3 = 0 \][/tex]
Simplify the expression inside the equation:
[tex]\[ x^2 - 2x \cdot 4 + 2x^2 - 3 = 0 \][/tex]
[tex]\[ x^2 - 8x + 2x^2 - 3 = 0 \][/tex]
[tex]\[ 3x^2 - 8x - 3 = 0 \][/tex]

3. Solve the quadratic equation [tex]\(3x^2 - 8x - 3 = 0\)[/tex] using the quadratic formula [tex]\(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\)[/tex]:
Here, [tex]\(a = 3\)[/tex], [tex]\(b = -8\)[/tex], and [tex]\(c = -3\)[/tex].

[tex]\[ x = \frac{-(-8) \pm \sqrt{(-8)^2 - 4 \cdot 3 \cdot (-3)}}{2 \cdot 3} \][/tex]
[tex]\[ x = \frac{8 \pm \sqrt{64 + 36}}{6} \][/tex]
[tex]\[ x = \frac{8 \pm \sqrt{100}}{6} \][/tex]
[tex]\[ x = \frac{8 \pm 10}{6} \][/tex]

- For the positive square root:
[tex]\[ x = \frac{8 + 10}{6} = \frac{18}{6} = 3 \][/tex]
- For the negative square root:
[tex]\[ x = \frac{8 - 10}{6} = \frac{-2}{6} = -\frac{1}{3} \][/tex]

4. Substitute these values of [tex]\(x\)[/tex] back into [tex]\(y = 4 - x\)[/tex]:
- When [tex]\(x = 3\)[/tex]:
[tex]\[ y = 4 - 3 = 1 \][/tex]
- When [tex]\(x = -\frac{1}{3}\)[/tex]:
[tex]\[ y = 4 - \left(-\frac{1}{3}\right) = 4 + \frac{1}{3} = \frac{12}{3} + \frac{1}{3} = \frac{13}{3} \][/tex]

Therefore, the algebraic solutions are:
[tex]\[ (x, y) = (3, 1) \quad \text{and} \quad \left(-\frac{1}{3}, \frac{13}{3}\right) \][/tex]

### Step 2: Graphical Solution

To graphically solve the equations, we need to plot both equations and find their intersections.

1. Equation 1:
[tex]\[ x + y = 4 \quad \text{or} \quad y = 4 - x \][/tex]
This is a straight line with slope [tex]\(-1\)[/tex] and y-intercept 4.

2. Equation 2:
[tex]\[ x^2 - 2xy - 3 = 0 \][/tex]

We can rewrite this as:
[tex]\[ y = \frac{x^2 - 3}{2x} \][/tex]
This represents a hyperbola, as there are [tex]\((x, y)\)[/tex] values which are obtained through the same algebraic manipulation as shown above.

3. Plot the equations:

- The straight line [tex]\(y = 4 - x\)[/tex]
- The hyperbola derived from [tex]\(x^2 - 2xy - 3 = 0\)[/tex]

By plotting both, you'll find the intersection points, confirming the algebraic solutions [tex]\((3, 1)\)[/tex] and [tex]\(\left(-\frac{1}{3}, \frac{13}{3}\right)\)[/tex].

The following graphical representation shows the system:

[tex]\[ \begin{array}{c} \text{Graph for } y = 4 - x \text{ and } y = \frac{x^2 - 3}{2x}: \\ \text{(Graph not actually shown here) } \end{array} \][/tex]

This completes the algebraic and graphical solutions for the system of equations. The intersection points observed graphically would match the solutions found algebraically: [tex]\((3, 1)\)[/tex] and [tex]\(\left(-\frac{1}{3}, \frac{13}{3}\right)\)[/tex].