Find the value of the polynomial 3x³ - 4x² + 7x - 5, when x = 3 and also when x = -3
Solution:
Given, the polynomial is 3x³ - 4x² + 7x - 5.
We have to find the value of the polynomial at x = 3 and x = -3.
Let p(x) = 3x³ - 4x² + 7x - 5
p(3) = 3(3)³ - 4(3)² + 7(3) - 5
= 3(27) - 4(9) + 21 - 5
= 81 + 21 - 36 - 5
= 102 - 41
= 61
Therefore, at x = 3 the value of the polynomial is 61.
p(-3) = 3(-3)³ - 4(-3)² + 7(-3) - 5
= 3(-27) - 4(9) - 21 - 5
= -81 - 36 - 26
= -81 - 62
= -143
Therefore, at x = -3 the value of the polynomial is -143.
✦ Try This: Find the value of the polynomial x³ + x² + x + 5, when x = 2 and also when x = -4.
☛ Also Check: NCERT Solutions for Class 9 Maths Chapter 2
NCERT Exemplar Class 9 Maths Exercise 2.3 Problem 7
Find the value of the polynomial 3x³ - 4x² + 7x - 5, when x = 3 and also when x = -3
Summary:
A polynomial is a type of expression in which the exponents of all variables should be a whole number. The value of the polynomial 3x³ - 4x² + 7x - 5 at x = 3 and x = -3 are 61 and -143
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