Answer:
Always
Step-by-step explanation:
The definition of a perpendicular line is that it intersects another at a 90 degree angle. Using this, by verticals, the opposite corner angle must also be 90-degrees, and since one side of a line is 180 degrees, 180-90 = 90, which ensure the rest of the angles will be 90 degrees too.
X^2 - 7x + 12 = 0
x^2 - 4x - 3x + 12 = 0
x (x - 4) -3 ( x - 4) = 0
(x - 4) (x - 3) = 0
x = 3 , 4
Check the answer by plugging in 3 and 4 for x, if the equation equals zero then you have your answer.