Sample Paper 3 Paper 2 Q.2(c)

Was requested to provide solution to "Sec 1 q 8" and am not sure what this refers to?
SEC A Q8 is a differentiation question which we haven't covered yet.

The trick in this question is in the first step i.e. multiplying by (x + 1)^2 
After that you could expand and solve the quadratic giving the solutions -2 and -1.
The region test below could also be done by considering the quadratic graph.
See examples in uploaded video below.

This is a financial maths and geometric series question.

Though this question is mostly relating to exponential equations part b is a differentiation question which we have not covered yet.