Question
Mathematics Question on Algebraic Expressions
If p=–2,find the value of: (i)4p+7 (ii) –3p2+4p+7 (iii)–2p3–3p2+4p+7
Answer
(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]