question_answer 1)

If \[p=-2,\] find the value of : (i) \[4p+7\]                         (ii) \[-3{{p}^{2}}+4p+7\]                (iii) \[-2{{p}^{3}}-3{{p}^{2}}+4p+7\]

Answer:

                (i) \[4p+7=4(-2)+7=-8+7=-1\].                 (ii) \[-3{{p}^{2}}+4p+7=-3{{(-2)}^{2}}+4(-2)+7\]                 \[=-12-8+7=-20+7\]                 \[=-13\].                 (iii) \[-2{{p}^{3}}-3{{p}^{2}}+4p+7=-2{{(-2)}^{3}}-3{{(-2)}^{2}}+4(-2)+7\]                 \[=-2(-8)-3(4)-8+7\]                 \[=16-12-8+7\]                 \[=16+7-12-8\]                 \[=23-20=3\].