Answer:
Step-by-step explanation:
4x -10y= 40
Let's rewrite this equation in the slope-intercept form (y= mx +c) so that we can obtain it's slope.
10y= 4x -40
Divide both side by 10:
The product of the gradients of perpendicular lines is -1.
⅖(gradient of line)= -1
Gradient of perpendicular line
Consider expression First, you can factor it:
Since x is integer number, then you can see that x-1 is previous integer number (x-1 is 1 unit smaller than x).
Therefore, x-1 and x are two consecutive integers. When you have two consecutive integers, one of them is always even and one is always odd. Multiplying even integer number by odd integer number you always get even integer number.
Thus, is always even.