1.

A parallelogram PQRS with area ($\displaystyle 1+2\sqrt{7}$) $\displaystyle units^2$ has length PQ ($\displaystyle 3+\sqrt{7}$) units. Given that the distance between the two parallel sides, SR and PQ is ($\displaystyle a+b\sqrt{c}$) units where a, b and c are integers. Find, without using a calculator, the values of a, b and c.

2.

Given that $\displaystyle y=18+ax^b$ , y=56 when x=4 and y=20 when x=2.5, find the value of a and b.