
Answer:
The line x -y=4 is perpendicular to the line x+y=9.
Step-by-step explanation:
Here, the equation Line 1 : x - y = 4
and the equation Line 2 : x + y = 9
Now, in the STANDARD FORM OF LINE EQUATION:
y = m x + c, here m = slope of the equation.
Line 1 transforms into : y = x - 4
⇒ Here, slope m 1 = 1
Line 2 transforms into : y = -x + 9
⇒ Here, slope m 2 = -1
Any two given lines in the Cartesian Plane are said to be perpendicular to each other if the product of their slopes is -1
Here, m1 x m2 = (1) x (-1) = (-1)
Hence, the line x -y=4 is perpendicular to the line x+y=9.