\(a,\left(x+574\right)\times87=57246\\ \Rightarrow x+574=57246:87\\ \Rightarrow x+574=658\\ \Rightarrow x=658-574\\ \Rightarrow x=87\\ b,x:68+685=784\\ \Rightarrow x:68=784-685\\ \Rightarrow x:68=99\\ \Rightarrow x=99\times68\\ \Rightarrow x=6732\)
\(\text{( x + 574 ) × 87 = 57246}\)
\(\left(x+574\right)=658\)
\(x=658-547\)
\(=111\)
\(\text{ b. x : 68 + 685 = 754}\)
\(x:68=754-685=69\)
\(x=69\times68\)
\(x=4692\)