4.

Solve the system using elimination.

5x = –25 + 5y
10y = 42 + 2x

(5, 10)

(–1, 4)

(–1, 2)

(4, –1)

1 answer

To solve the system using elimination, let's start by rewriting the given equations in a standard form:

1) \( 5x - 5y = -25 \)
2) \( 2x - 10y = -42 \)

Step 1: Simplify the first equation.

Divide the first equation by 5:
\[ x - y = -5 \]

Step 2: Simplify the second equation.

Divide the second equation by 2:
\[ x - 5y = -21 \]

Now we have the system:
1) \( x - y = -5 \)
2) \( x - 5y = -21 \)

Step 3: Eliminate \( x \).

Subtract the first equation from the second equation:
\[ (x - 5y) - (x - y) = -21 - (-5) \]
\[ x - 5y - x + y = -21 + 5 \]
\[ -4y = -16 \]

Solve for \( y \):
\[ y = 4 \]

Step 4: Substitute \( y \) back into the first equation to solve for \( x \).

Substitute \( y = 4 \) into \( x - y = -5 \):
\[ x - 4 = -5 \]
\[ x = -1 \]

So, the solution to the system is \( (x, y) = (-1, 4) \).

Thus, the correct answer is: \((–1, 4)\).