College

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 solve this problem, we need to understand what the question is asking. We have the following system of equations:

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

We need to determine which equation can be derived from this system. The system gives us two expressions for [tex]\( y \)[/tex], which means these two expressions are equal to each other. To find the common equation they satisfy, we should set the expressions equal to each other:

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

This equation is the key to solving the problem. Now, let's compare this equation with the options given:

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

The equation we derived, [tex]\( 3x^3 - 7x^2 + 5 = 7x^4 + 2x \)[/tex], directly matches option 2.

Therefore, the correct answer is:

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