The line equation in slope-intercept form is given by

where b is the y-intercept and m is the slope.
Then, we need to convert the given equation into the slope-intercept form. Then, by subtracting 10x to both sides, we have

and by dividing both sides by 2, we get

By comparing this result with the first equation, we can see that the slope is m= -5. So, the answer is: -5