Let's solve the equations separately:

(7-0,2x)1,4=7,56
First, distribute the 1.4 to the expression inside the parentheses:
71.4 - 0.2x*1.4 = 7.56
9.8 - 0.28x = 7.56
Now, isolate x by moving the constant to the other side:
-0.28x = 7.56 - 9.8
-0.28x = -2.24
Finally, divide by -0.28 to solve for x:
x = -2.24 / -0.28
x ≈ 8

(6.1x-13.2)/1.7=3
First, multiply both sides by 1.7:
6.1x - 13.2 = 3 * 1.7
6.1x - 13.2 = 5.1
Now, isolate x by moving the constant to the other side:
6.1x = 5.1 + 13.2
6.1x = 18.3
Finally, divide by 6.1 to solve for x:
x = 18.3 / 6.1
x = 3

Therefore, the solutions are x ≈ 8 and x = 3.