Use the substitution method to find the solutions to the linea-quadratic system

y = 2x − 3


y = x2 + 6x − 3

1 answer

To solve the given system of equations using the substitution method, we have the following equations:

  1. \( y = 2x - 3 \)
  2. \( y = x^2 + 6x - 3 \)

Since both equations are equal to \( y \), we can set them equal to each other:

\[ 2x - 3 = x^2 + 6x - 3 \]

Next, we can simplify this equation. First, add 3 to both sides to eliminate -3:

\[ 2x = x^2 + 6x \]

Now, subtract \( 2x \) from both sides:

\[ 0 = x^2 + 6x - 2x \]

This simplifies to:

\[ 0 = x^2 + 4x \]

Now, we can factor the right side:

\[ 0 = x(x + 4) \]

Setting each factor equal to zero gives us the possible solutions for \( x \):

  1. \( x = 0 \)
  2. \( x + 4 = 0 \) which gives \( x = -4 \)

Now that we have the values for \( x \), we can substitute these values back into the first equation, \( y = 2x - 3 \), to find the corresponding values of \( y \).

  1. For \( x = 0 \): \[ y = 2(0) - 3 = -3 \] So, one solution is \( (0, -3) \).

  2. For \( x = -4 \): \[ y = 2(-4) - 3 = -8 - 3 = -11 \] So, another solution is \( (-4, -11) \).

Thus, the solutions to the system of equations are:

\[ (0, -3) \quad \text{and} \quad (-4, -11) \]