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

y = 2x − 3


y = x2 + 6x − 3




(1 point)
Responses

(1, -1) and (2, 1)
(1, -1) and (2, 1)

(-4, -11) and (0, -3)
(-4, -11) and (0, -3)

(-4, -11)
(-4, -11)

(0, -3)

1 answer

To solve the system of equations using the substitution method, we start with the given equations:

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

Since we have \( y \) expressed in terms of \( x \) in the first equation, we can substitute \( 2x - 3 \) for \( y \) in the second equation.

Substituting, we have:

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

Now, we will simplify and solve for \( x \):

  1. Add \( 3 \) to both sides:

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

  1. Rearranging gives us:

\[ 0 = x^2 + 6x - 2x \] \[ 0 = x^2 + 4x \]

  1. Factor the quadratic equation:

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

Setting each factor to zero gives:

\[ x = 0 \quad \text{or} \quad x + 4 = 0 \Rightarrow x = -4 \]

Now, we can find the corresponding \( y \) values by substituting back into the first equation:

  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, the other solution is \( (-4, -11) \).

Thus, the solutions to the system are:

  • \( (0, -3) \)
  • \( (-4, -11) \)

Considering the possible responses given:

  • (1, -1) and (2, 1)
  • (-4, -11) and (0, -3)
  • (-4, -11)
  • (0, -3)

The correct choice is:

(-4, -11) and (0, -3).