Question

find the value of the polynomial 3x^3-4x^2+7x-5 when x=3 and also when x=-3

Answer 1

at x=3:-
3(3)^3-4(3)^2+7(3)-5=3*27-4*9+21-5=61
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when x= -3
3*(-3)^3-4*(-3)^2+7*(-3)-5=  3*(-27)-4*9+7*(-3)=-143
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Answer 2

Answer:

Step-by-step explanation:

Let p(x) =3x3 – 4x2 + 7x – 5

At x= 3, p(3) = 3(3)3 – 4(3)2 + 7(3) – 5

= 3×27-4×9 + 21-5 = 81-36+21-5 P( 3) =61

At x = -3, p(-3)= 3(-3)3 – 4(-3)2 + 7(-3)- 5

= 3(-27)-4×9-21-5 = -81-36-21-5 = -143 p(-3) = -143

Hence, the value of the given polynomial at x = 3 and x = -3 are 61 and -143, respectively.