To solve the system of equations given:
- \( 16x^2 + 8xy + y^2 = 36 \) (Equation 1)
- \( 3x - y = 8 \) (Equation 2)
We can start by solving Equation 2 for \( y \):
\( y = 3x - 8 \) (Substituting this in Equation 1)
Now, substitute \( y \) in Equation 1:
\[ 16x^2 + 8x(3x - 8) + (3x - 8)^2 = 36 \]
Next, we simplify this. First, calculate \( 8x(3x - 8) \):
\[ 8x(3x - 8) = 24x^2 - 64x \]
Now, calculate \( (3x - 8)^2 \):
\[ (3x - 8)^2 = 9x^2 - 48x + 64 \]
Substituting these back into Equation 1 gives:
\[ 16x^2 + (24x^2 - 64x) + (9x^2 - 48x + 64) = 36 \]
Combine the like terms:
\[ 16x^2 + 24x^2 + 9x^2 - 64x - 48x + 64 = 36 \] \[ 49x^2 - 112x + 64 = 36 \]
Now, subtract 36 from both sides:
\[ 49x^2 - 112x + 28 = 0 \]
Next, we can use the quadratic formula \( x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \), where \( a = 49 \), \( b = -112 \), and \( c = 28 \).
Calculate the discriminant:
\[ b^2 - 4ac = (-112)^2 - 4 \cdot 49 \cdot 28 \]
Calculate that step-by-step:
First, find \( (-112)^2 \):
\[ 12444 = 12544 \] Now, find \( 4 \cdot 49 \cdot 28 \):
\[ 4 \cdot 49 = 196 \] \[ 196 \cdot 28 = 5488 \]
Now calculate:
\[ 12544 - 5488 = 7056 \]
Now, since the discriminant is positive, we proceed:
Calculate the square root:
\[ \sqrt{7056} = 84 \]
So, applying the quadratic formula:
\[ x = \frac{112 \pm 84}{98} \]
Now calculate \( x \):
- \( x = \frac{196}{98} = 2 \)
- \( x = \frac{28}{98} = \frac{14}{49} = \frac{2}{7} \)
Compute \( y \) for each value of \( x \):
- For \( x = 2 \):
\[ y = 3(2) - 8 = 6 - 8 = -2 \]
- For \( x = \frac{2}{7} \):
\[ y = 3 \left(\frac{2}{7}\right) - 8 = \frac{6}{7} - 8 = \frac{6 - 56}{7} = \frac{-50}{7} \]
Thus, the solutions to the system of equations are:
\[ (2, -2) \quad \text{and} \quad \left(\frac{2}{7}, \frac{-50}{7}\right) \]