Get comprehensive solutions to your questions with the help of IDNLearn.com's experts. Join our community to receive timely and reliable responses to your questions from knowledgeable professionals.

Solve the system of equations:

[tex]\[
\begin{array}{l}
3xy - y^2 = 8 \\
x - 2y = 1
\end{array}
\][/tex]


Sagot :

Certainly! Let's solve the given system of equations step by step.

We have the following system of equations:

1. [tex]\( 3xy - y^2 = 8 \)[/tex]
2. [tex]\( x - 2y = 1 \)[/tex]

### Step 1: Express [tex]\( x \)[/tex] in terms of [tex]\( y \)[/tex] using the second equation

Starting with the second equation:
[tex]\[ x - 2y = 1 \][/tex]

We can solve for [tex]\( x \)[/tex] as follows:
[tex]\[ x = 1 + 2y \][/tex]

### Step 2: Substitute [tex]\( x \)[/tex] in the first equation

Now we substitute [tex]\( x = 1 + 2y \)[/tex] into the first equation:
[tex]\[ 3(1 + 2y)y - y^2 = 8 \][/tex]

Distribute [tex]\( y \)[/tex] through the parentheses:
[tex]\[ 3y + 6y^2 - y^2 = 8 \][/tex]

Combine like terms:
[tex]\[ 3y + 5y^2 = 8 \][/tex]

### Step 3: Form a quadratic equation

We have the quadratic equation:
[tex]\[ 5y^2 + 3y - 8 = 0 \][/tex]

### Step 4: Solve the quadratic equation

To find the values of [tex]\( y \)[/tex], we can use the quadratic formula [tex]\( y = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \)[/tex], where [tex]\( a = 5 \)[/tex], [tex]\( b = 3 \)[/tex], and [tex]\( c = -8 \)[/tex]:

[tex]\[ y = \frac{-3 \pm \sqrt{3^2 - 4 \cdot 5 \cdot (-8)}}{2 \cdot 5} \][/tex]
[tex]\[ y = \frac{-3 \pm \sqrt{9 + 160}}{10} \][/tex]
[tex]\[ y = \frac{-3 \pm \sqrt{169}}{10} \][/tex]
[tex]\[ y = \frac{-3 \pm 13}{10} \][/tex]

This gives us two solutions for [tex]\( y \)[/tex]:

[tex]\[ y = \frac{-3 + 13}{10} = \frac{10}{10} = 1 \][/tex]
[tex]\[ y = \frac{-3 - 13}{10} = \frac{-16}{10} = -\frac{8}{5} \][/tex]

### Step 5: Find corresponding [tex]\( x \)[/tex] values

Now, substitute each value of [tex]\( y \)[/tex] back into the expression [tex]\( x = 1 + 2y \)[/tex] to find the corresponding [tex]\( x \)[/tex] values:

For [tex]\( y = 1 \)[/tex]:
[tex]\[ x = 1 + 2 \cdot 1 = 1 + 2 = 3 \][/tex]

For [tex]\( y = -\frac{8}{5} \)[/tex]:
[tex]\[ x = 1 + 2 \cdot \left(-\frac{8}{5}\right) = 1 - \frac{16}{5} = \frac{5}{5} - \frac{16}{5} = -\frac{11}{5} \][/tex]

### Step 6: Write the solution set

The solutions to the system of equations are:
[tex]\[ (x, y) = \left(3, 1\right) \][/tex]
[tex]\[ (x, y) = \left(-\frac{11}{5}, -\frac{8}{5}\right) \][/tex]

Thus, the solution set is:
[tex]\[ \boxed{\left\{\left(3, 1\right), \left(-\frac{11}{5}, -\frac{8}{5}\right)\right\}} \][/tex]