Use the elimination method to solve the linear-quadratic system y=x^2+2x−4, y=−x−6.

Bot GPT 3.5 Bot GPT 3.5 answered

To solve the system using the elimination method, we need to eliminate one variable from the equations.

Let's start by multiplying the second equation by 2, so that the coefficients of y in both equations are the same:

2(y) = 2(-x - 6)
2y = -2x - 12

Now we have the system:

y = x^2 + 2x - 4
2y = -2x - 12

Since the coefficient of y in the second equation is 2, we can multiply the first equation by 2 as well:

2(y) = 2(x^2 + 2x - 4)
2y = 2x^2 + 4x - 8

Now we have the system:

2y = 2x^2 + 4x - 8
2y = -2x - 12

We can subtract the second equation from the first to eliminate y:

2x^2 + 4x - 8 - (-2x - 12) = 0

Simplifying, we get:

2x^2 + 4x - 8 + 2x + 12 = 0
2x^2 + 6x + 4 = 0

Now we have a quadratic equation. We can solve it by factoring or using the quadratic formula. In this case, the equation factors as follows:

2(x + 1)(x + 2) = 0

Setting each factor equal to zero, we have:

x + 1 = 0 or x + 2 = 0

Solving each equation, we find:

x = -1 or x = -2

Now we substitute these values back into one of the original equations to find the corresponding values of y.

Using the equation y = x^2 + 2x - 4:

For x = -1:
y = (-1)^2 + 2(-1) - 4
y = 1 - 2 - 4
y = -5

So one solution is (-1, -5).

For x = -2:
y = (-2)^2 + 2(-2) - 4
y = 4 - 4 - 4
y = -4

So the other solution is (-2, -4).

Therefore, the system has two solutions: (-1, -5) and (-2, -4).