Answer:
3x = - 18
Step-by-step explanation:
1. Simplify this equation in terms of what is already provided:
3x + 4 = 5x - 4x - 8 ⇒ 3x + 4 = x - 8
2. Now subtract 3x from either side, at the same time adding 8 to either side: 3x + 4 = x - 8 ⇒ 4 = -2x - 8 ⇒ 12 = -2x
3. Divide -2 on either side to isolate the x, and recieve it's value:
12 = -2x ⇒ x = 12/-2 ⇒ x = -6
4. The question demads for the value of 3x, so simply multiply the known value of x by 3, as such: x = -6 ⇒ 3x = -6 * 3 = -18
