Answer:
x = -10 13/15
Explanation:
3/4(-4.2 - x) = 5
4/3 * (3/4(-4.2 - x) = 5) ==> multiply by the reciprocal of a number to get 1
1(-4.2 - x) = 5 * 4/3
-4.2 - x = 20/3
-4 2/10 - x = 20/3
-(4 + 2/10) - x = 20/3
-(40/10 + 2/10) - x = 20/3
-42/10 - x = 20/3
42/10 - 42/10 - x = 42/10 + 20/3
-x = 42/10 + 20/3
30 * (-x = 42/10 + 20/3) ==> LCM(Least common multiple) of 10 and 3 is 30.
-30x = 30 * 42/10 + 30 * 20/3
-30x = 30/10 * 42 + 30/3 * 20
-30x = 3 * 42 + 10 * 20
-30x = 126 + 200
-30x = 326
30x = -326
x = -326/30
x = -(300 + 26)/30
x = -300/30 - 26/30
x = -10 - 26/30
x = -(10 + 26/30)
x = -10 26/30
x = -10 13/15