What is the substitution of -6x-8y=-20 and x+6y=-6

Substitution doesn't work for this, but elimination does.

-6x-8y=-20 +6( x+6y=-6)

-6x-8y=-20 + 6x+36y=-36

-6x and 6x cancel each other, add -8 and 36 to get 28, and -20 and -36 to get -56.

28y=-56

divide by 28 on both sides.

Y= -2

Then substitute y into one of the equations.

x+6(-2)=-6

x-12=-6

x=6

The ordered pair is (6,-2).

x=-4/3y+10/3 and x=-6-6y

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.