To solve the system of equations
- \(3x - 4y = 40\)
- \(5x - 5y = 55\)
we can follow these steps:
First, simplify the second equation: \[ 5x - 5y = 55 \implies x - y = 11 \implies x = y + 11 \]
Now, substitute \(x\) in the first equation: \[ 3(y + 11) - 4y = 40 \] \[ 3y + 33 - 4y = 40 \] \[ -y + 33 = 40 \] \[ -y = 40 - 33 \] \[ -y = 7 \implies y = -7 \]
Now substitute \(y\) back into the equation for \(x\): \[ x = y + 11 = -7 + 11 = 4 \]
Thus, the solution to the system of equations is: \[ (x, y) = (4, -7) \]
Therefore, the correct answer is: \((4, -7)\)