a)
\(280-\dfrac{\left(x-140\right)}{35}=270\\\dfrac{ \left(x-140\right)}{35}=10\\ x-140=\dfrac{10}{35}\\ x=\dfrac{10}{35}+140=\dfrac{982}{7}\)
b)
\(\dfrac{\left(190-2x\right)}{35}-32=16\\ \dfrac{\left(190-2x\right)}{35}=48\\ 190-2x=1680\\ -2x=1490\\ x=-745\)
c)
\(\dfrac{720}{41-2x+5}=2^3.5\\ \dfrac{720}{46-2x}=40\\ 720=1840-80x\\ 80x=1120\\ x=14\)