Divide nine by three, then subtract two double the results

-3

Step-by-step explanation:

because nine divided by 3 is 3 then subtract 3 which is 0 then subtract 3 again which is -3

last option

step-by-step explanation:

given that δdef is right and isoceles,

assuming that side df is the hypotenuse means that de an ef are the other 2 sides that intersect at 90° and are of equal length.

because they are of equal length, we can say that they are congruent

because they intersect at 90°, their slopes must be opposite reciprocals.

only the last option satisfies these conditions.