(a)f(x)isapolynomialfunctionandhencecontinuousin[1,2](b)f(x)isapolynomialfunctionandhencedifferentiablein(1,2)thenf′(c)=(f(2)−f(1)2−1)2c−3=(2−2)/1∴c=(32)∈[1,2]Henceverified