Let's solve for x step by step:

Distribute the negative sign on the right side of the equation:
1,7 - (x - 6,2) = -(8,5 + 3x)
1,7 - x + 6,2 = -8,5 - 3x

Combine like terms on both sides of the equation:
7,9 - x = -8,5 - 3x

Add x to both sides to get rid of x on the left side:
7,9 = -8,5 - 3x + x
7,9 = -8,5 - 2x

Add 8,5 to both sides to get rid of the constant term on the right side:
7,9 + 8,5 = -2x
16,4 = -2x

Divide by -2 to solve for x:
x = -16,4 / -2
x = 8,2

Therefore, the solution to the equation is x = 8,2.