Answer:
x=-10
Step-by-step explanation:
2(x+3)=x-4 (Multiply the 2 by the x and the 3);
2x+6=x-4 (Now you group like terms)
2x-x=-4-6
x=-10
Answer: x=4
Steps: (I am assuming your question has a typo in it and by "c" you meant "x")
The rational expression equals zero

only when the numerator equals 0 (the denominator cannot ever be zero):

and that happens only for x=4
Answer:
z = 7
Step-by-step explanation:
4z - 8 = 20
Add 8 to each side
4z - 8+8 = 20+8
4z = 28
Divide each side by 4
4z/4 = 28/4
z = 7