If p = -2, find the value of:
(i) 4p + 7   (ii) - 3p² + 4p + 7   (iii) - 2p³ - 3p² + 4p + 7

Solution:

Let us find the value of given expression by substituting the value of p as -2.

(i) 4p + 7

= 4 × (-2) + (7)

= - 8 + 7

= - 1 

(ii) - 3p² + 4p + 7

= -3 × (-2)² + 4 × (-2) + 7

= -3 × (-2) × (-2) + (-8) + 7

= -12 - 8 + 7

= -13 

(iii) - 2p³ - 3p² + 4p + 7

= -2(-2)³ - 3(-2)² + 4(-2) + 7

= -2 × (-2) × (-2) × (-2) - 3 × (-2) × (-2) + 4 × (-2) + 7

= 16 - 12 + (-8) + 7

= 3 

☛ Check: NCERT Solutions for Class 7 Maths Chapter 12

Video Solution:

If p = - 2, find the value of: (i) 4p + 7(ii) -3p² + 4p + 7 (iii) -2p³ - 3p² + 4p + 7

Maths NCERT Solutions Class 7 Chapter 12 Exercise 12.3 Question 2

Summary:

If p = -2, the value of: (i) 4p + 7 = -1 (ii) -3p² + 4p + 7 = -13 (iii) -2p³ - 3p² + 4p + 7 = 3

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