High School

Which equation can be solved by using this system of equations?

[tex]
\[
\begin{cases}
y = 3x^3 - 7x^2 + 5 \\
y = 7x^4 + 2x
\end{cases}
\]
[/tex]

A. [tex]3x^3 - 7x^2 + 5 = 0[/tex]

B. [tex]3x^3 - 7x^2 + 5 = 7x^4 + 2x[/tex]

C. [tex]7x^4 + 2x = 0[/tex]

D. [tex]7x^4 + 3x^3 - 7x^2 + 2x + 5 = 0[/tex]

Answer :

To determine which equation can be solved using the given system of equations, let's take a closer look at the system provided:

The system consists of two equations:
1. [tex]\( y = 3x^3 - 7x^2 + 5 \)[/tex]
2. [tex]\( y = 7x^4 + 2x \)[/tex]

To find an equation that can be solved, we need to identify when these two expressions for [tex]\( y \)[/tex] are equal, which means setting the right-hand sides equal to each other:

[tex]\[ 3x^3 - 7x^2 + 5 = 7x^4 + 2x \][/tex]

This is the equation you get when solving this system by equating the two expressions for [tex]\( y \)[/tex].

We can also rearrange this equation by bringing all terms to one side to simplify or solve it further. So, subtract the entire right side [tex]\( 7x^4 + 2x \)[/tex] from both sides:

[tex]\[ 3x^3 - 7x^2 + 5 - (7x^4 + 2x) = 0 \][/tex]

Simplifying, we get:

[tex]\[ 7x^4 + 3x^3 - 7x^2 + 2x - 5 = 0 \][/tex]

Therefore, the equation you can solve using the system of equations is:

[tex]\[ 3x^3 - 7x^2 + 5 = 7x^4 + 2x \][/tex]
or in its rearranged form:
[tex]\[ 7x^4 + 3x^3 - 7x^2 + 2x - 5 = 0 \][/tex]

These equations involve equating and manipulating the system equations provided.