Consider the two expressions $\frac{4x^3+2x^2+6x+7}{2x+1}$ and $2x^2+3+\frac4{2x+1}.$ a) show that the two expressions are equal to each other when $x=10.$ b) explain why these two expressions are not equal to each other when $x=-\dfrac12.$ c) show that these two expressions are equal to each other for all $x$ other than $-\dfrac12.$