Hi !

Question a).

A quadratic equation has one and only one solution if it is proportional to a perfect square.

This means that you want to be a perfect square.

The discriminant should be equal to 0.

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Question b)

two parallel lines have the same slope. Here, the slope is 8.

A tangent line to the curve representing a function f(x) has this equation :

So actually, you have to solve for .

Is it clear enough ? Because I didn't understand what X0' was...

And then I had this log equation, and if someone would check if it's right, that'd make me very happy. (:

Just check, in this kind of exercises, that the answer fits in the domain of the equation.

that is to say 2x+7>0 and x>0