First, recall that Gaussian quadrature is based around integrating a function over the interval [-1,1], so transform the function argument accordingly to change the integral over [1,5] to an equivalent one over [-1,1].



So,

Let

. With

, we're looking for coefficients

and nodes

, with

, such that

You can either try solving for each with the help of a calculator, or look up the values of the weights and nodes (they're extensively tabulated, and I'll include a link to one such reference).
Using the quadrature, we then have

Answer:
3/4x-6=42
x=64
Step-by-step explanation:
Let the number of students be x hence 3/4 of this number will be 3/4x
Since the number was 42 if they were 3/4x less six, it means minus six hence
3/4x-6=42
Therefore, the equation will be
3/4x-6=42
Solving the equation
3/4 x=42+6=48
3/4x=48
X=62
So you cannot really get the exact measure because they didn't give you any measures, but we can infer that if c>b and a then
maybe SX (d) is more than b and a so
a<b<c or d not sure which
sorry if I didn't help