Algebra: Solve & Substitute

1. If $6x + 3y = 9$ and $6y=78$, what is the value of $2x=$?

(A) -10

(B)10 

(C)-5

(D)-2

(E) -25

2. If $\dfrac{5}{6}$ of $x=60$, then $\dfrac{1}{4}$ of $x=$

(A) 18

(B) 50

(C) 72

(D) 12.5

(E) 13

3. If $x-2y=12$ and $x=4$, then $3y-7=$ 

(A) -19

(B) -8

(C) -31

(D) 4

(E) -4

4. If $9(x-4)=36$, then what is $x-4$?

Grid in your answer.