a) Simplify the following expression giving your answer in standard form:
(2.8 x 10^3) x (4.2 x 10^2)
b) Solve the following pair of simultaneous equations, clearly showing your working out of the solution: {8x-2y = -6 3x + y = 17
c) Solve the following double inequality: -5 <2x+3<7 [10 marks]