(i) 4p+7 = 4(-2)+7 = -8+7 = -1 [putting p = -2]
(ii) -3p2 + 4p+7 = -3(-2)2+4(-2)+7 = -3×4-8+7 = -12-8+7 = -20+7 = -13 [putting p = -2]
(iii) -2p3-3p2+4p+7 = -2(-2)3-3(-2)2+4(-2)+7 = -2×(-8)-3×4-8+7 = 16-12-8+7 = -20+23 = 3 [putting p = -2]
The bulb in the circuit shown in Fig. does not glow. Can you identify the problem? Make necessary changes in the circuit to make the bulb glow.