Ineed solving this! i need and answer fast

Solve the porportions. First, cross multiply

7/(x - 4) = 42/12

(7/(x-4))(x-4)(12) = (42/12)(12)(x-4)

7(12) = 42(x-4)

Simplify. (remember to distribute the 42 to both x and -4

84 = 42x - 168

Isolate the x. First add 168 to both sides

84 (+168) = 42x - 168 (+168)

42x = 84 + 168

42x =  252

Finally, isolate the x by dividing 42 from both sides

42x/42 = 252/42

x = 252/42

x = 6

6 is your answer

hope this helps