College

Which system is equivalent to

[tex]\[

\left\{

\begin{array}{l}

5x^2 + 6y^2 = 50 \\

7x^2 + 2y^2 = 10

\end{array}

\right.

\][/tex]

A.
[tex]\[

\left\{

\begin{aligned}

5x^2 + 6y^2 &= 50 \\

-21x^2 - 6y^2 &= 10

\end{aligned}

\right.

\][/tex]

B.
[tex]\[

\left\{

\begin{aligned}

5x^2 + 6y^2 &= 50 \\

-21x^2 - 6y^2 &= 30

\end{aligned}

\right.

\][/tex]

C.
[tex]\[

\left\{

\begin{aligned}

35x^2 + 42y^2 &= 250 \\

-35x^2 - 10y^2 &= -50

\end{aligned}

\right.

\][/tex]

D.
[tex]\[

\left\{

\begin{aligned}

35x^2 + 42y^2 &= 350 \\

-35x^2 - 10y^2 &= -50

\end{aligned}

\right.

\][/tex]

Answer :

To solve the problem of finding which system is equivalent to the given system of equations:

[tex]\[
\left\{
\begin{array}{l}
5x^2 + 6y^2 = 50 \\
7x^2 + 2y^2 = 10 \\
\end{array}
\right.
\][/tex]

we're going to manipulate these equations to see which option matches after manipulation.

### Step 1: Align the [tex]\( x^2 \)[/tex] terms for elimination

Multiply the first equation by 7 and the second equation by 5 to make the coefficients of [tex]\( x^2 \)[/tex] the same:

1. Multiply the first equation by 7:
[tex]\[
7(5x^2 + 6y^2 = 50) \implies 35x^2 + 42y^2 = 350
\][/tex]

2. Multiply the second equation by 5:
[tex]\[
5(7x^2 + 2y^2 = 10) \implies 35x^2 + 10y^2 = 50
\][/tex]

### Step 2: Subtract the second transformed equation from the first

Now subtract the newly formed second equation from the first to eliminate [tex]\( x^2 \)[/tex]:

[tex]\[
(35x^2 + 42y^2) - (35x^2 + 10y^2) = 350 - 50
\][/tex]

This simplifies to:

[tex]\[
42y^2 - 10y^2 = 300
\][/tex]

[tex]\[
32y^2 = 300
\][/tex]

The subtraction between left-hand sides doesn't fully match a typical representation here, indicating that the focus should remain on eliminating the [tex]\( x^2 \)[/tex] terms, allowing us to match these with a given option instead.

### Step 3: Check for equivalent options

Let's consider the options to see if any align:
- Option 1:
[tex]\[
\left\{
\begin{aligned}
5x^2 + 6y^2 & = 50 \\
-21x^2 - 6y^2 & = 10
\end{aligned}
\right.
\][/tex]

- Option 2:
[tex]\[
\left\{
\begin{aligned}
5x^2 + 6y^2 & = 50 \\
-21x^2 - 6y^2 & = 30
\end{aligned}
\right.
\][/tex]

- Option 3:
[tex]\[
\left\{
\begin{aligned}
35x^2 + 42y^2 & = 250 \\
-35x^2 - 10y^2 & = -50
\end{aligned}
\right.
\][/tex]

- Option 4:
[tex]\[
\left\{
\begin{aligned}
35x^2 + 42y^2 & = 350 \\
-35x^2 - 10y^2 & = -50
\end{aligned}
\right.
\][/tex]

Comparing these with the results from multiplying and aligning [tex]\( x^2 \)[/tex], we see that Option 4 is the one that matches:

[tex]\[
\left\{
\begin{aligned}
35x^2 + 42y^2 & = 350 \\
-35x^2 - 10y^2 & = -50
\end{aligned}
\right.
\][/tex]

Thus, the correct answer is the system:

[tex]\[
\left\{
\begin{aligned}
35x^2 + 42y^2 & = 350 \\
-35x^2 - 10y^2 & = -50
\end{aligned}
\right.
\][/tex]