High School

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

[tex]
\[
\left\{
\begin{array}{l}
y = 3x^3 - 7x^2 + 5 \\
y = 7x^4 + 2x
\end{array}
\right.
\]
[/tex]

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

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

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

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

Answer :

To identify which equation can be solved using the given system of equations, let's go through the process step-by-step:

1. Understand the System of Equations:
- We have a system of two equations:
[tex]\[
\left\{\begin{array}{l}
y = 3x^3 - 7x^2 + 5 \\
y = 7x^4 + 2x
\end{array}\right.
\][/tex]

2. Set the Equations Equal to Each Other:
- Since both expressions are equal to [tex]\( y \)[/tex], we can set them equal to each other:
[tex]\[
3x^3 - 7x^2 + 5 = 7x^4 + 2x
\][/tex]

3. Rearrange the Equation:
- To form a single equation, we move all terms to one side of the equation:
[tex]\[
7x^4 + 3x^3 - 7x^2 + 2x + 5 = 0
\][/tex]
- This equation is derived by subtracting the left side from the right side, ensuring that all terms are on one side and the equation is set to zero.

4. Conclusion:
- The equation that can be solved using the given system of equations is:
[tex]\[
7x^4 + 3x^3 - 7x^2 + 2x + 5 = 0
\][/tex]

This step-by-step approach shows how we use the system of equations to derive the single equation that can be solved for [tex]\( x \)[/tex].