What is the solution to the following system of equations? -5x-4y=-4 25x+20y=20

Simplify
2nd one divide both sides by 5
5x+4y=4
hmm, seems familliar
times it by -1
-5x-4y=-4
same as other one

they are the same line
therefor the solution set is all the points on the line -5x-4y=-4 or y=(-5/4)x+1

solution set is alll points on y=(-5/4)x+1 or 5x+4y=4

For 13 a 0 degree line is a straight line