Question

4.
-5x + 7y = 12
-5x + 6y = 11

Explanation:

Step1: Subtract the two equations

$$(-5x + 7y) - (-5x + 6y) = 12 - 11$$

Step2: Simplify to solve for y

$$-5x + 7y + 5x - 6y = 1$$
$$y = 1$$

Step3: Substitute y=1 into first equation

$$-5x + 7(1) = 12$$

Step4: Solve for x

$$-5x = 12 - 7$$
$$-5x = 5$$
$$x = \frac{5}{-5} = -1$$

Answer:

$x=-1$, $y=1$