#0.5x^2+bx+8# How to choose b so that 6 children will be able to solve different inequalities and get different answers?
Just selecting six different values for 'b' should do it.
You question is not clear. The expression shown is not an inequality. Changing the 'b' term will necessarily change any solution to an equation or inequality when the other terms remain the same. Whether or not "children" will be able to solve any of them is another question.