-4z= 20
to get z alone, divide both sides by -4
-4z/-4= 20/-4
-4 on the left cancels out; divide 20 by -4
the answer will also be negative since 20 is positive and you need two negatives to make a positive
z= -5
CHECK:
(-4)(-5)= 20
20= 20
ANSWER: z= -5
Hope this helps! :)