A class of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"><mml:mi>p</mml:mi><mml:mtext>–</mml:mtext><mml:mi>q</mml:mi></mml:math>-Laplacian type equation with concave–convex nonlinearities in bounded domain