Answer:
x= -3 / 8
Step-by-step explanation:
5x+7+3x-4=0
Sum 5x and 3x
8x+7-4=0
Subtract 7-4
8x+3=0
Move the constant to the other side and change his symbol with his opposite
8x=-3
8 is multiplying x, the opposite of multiplying is dividing, so it divide the -3 (under it)
x= -3 / 8
