Solve the following system of equations. Show all work and solutions.

[tex]\[
\begin{array}{l}
y = 3x^2 + 6x + 4 \\
y = -3x^2 + 4
\end{array}
\][/tex]



Answer :

To solve the given system of equations:

[tex]\[ \begin{array}{l} y = 3x^2 + 6x + 4 \\ y = -3x^2 + 4 \end{array} \][/tex]

we start by setting the two expressions for [tex]\( y \)[/tex] equal to each other:

[tex]\[ 3x^2 + 6x + 4 = -3x^2 + 4 \][/tex]

Next, we get all the terms on one side to form a single equation:

[tex]\[ 3x^2 + 6x + 4 + 3x^2 - 4 = 0 \][/tex]

Simplify the equation:

[tex]\[ 6x^2 + 6x = 0 \][/tex]

Factor out the common term, which is [tex]\( 6x \)[/tex]:

[tex]\[ 6x(x + 1) = 0 \][/tex]

This gives us two solutions:

[tex]\[ 6x = 0 \quad \text{or} \quad x + 1 = 0 \][/tex]

Solving these, we find:

[tex]\[ x = 0 \quad \text{or} \quad x = -1 \][/tex]

Next, we find the corresponding [tex]\( y \)[/tex]-values for each [tex]\( x \)[/tex]-value by substituting back into one of the original equations. We'll use [tex]\( y = 3x^2 + 6x + 4 \)[/tex].

For [tex]\( x = 0 \)[/tex]:

[tex]\[ y = 3(0)^2 + 6(0) + 4 = 4 \][/tex]

For [tex]\( x = -1 \)[/tex]:

[tex]\[ y = 3(-1)^2 + 6(-1) + 4 = 3(1) - 6 + 4 = 3 - 6 + 4 = 1 \][/tex]

Thus, the solutions to the system of equations are:

[tex]\[ (x, y) = (0, 4) \quad \text{and} \quad (x, y) = (-1, 1) \][/tex]

So, the final solutions are [tex]\( x = 0 \)[/tex] with [tex]\( y = 4 \)[/tex] and [tex]\( x = -1 \)[/tex] with [tex]\( y = 1 \)[/tex].