Question

find the value of polynomial 4x²-5x (a)x=2 (b) x =5 (c)x=1/2
​

Answer 1

Answer:

a) 6

b) 75

c) -3/2

Solution:

Here ,

The given quadratic polynomial is ;

4x² - 5x .

We need to find the values of the given polynomial at x = 2 , 5 , 1/2 .

Thus,

Let the given quadratic polynomial be p(x) .

Thus,

p(x) = 4x² - 5x

★ At x = 2

=> p(x) = 4x² - 5x

=> p(2) = 4•2² - 5•2

=> p(2) = 16 - 10

=> p(2) = 6

★ At x = 5

=> p(x) = 4x² - 5x

=> p(5) = 4•5² - 5•5

=> p(5) = 100 - 25

=> p(5) =75

★ At x = 1/2

=> p(x) = 4x² - 5x

=> p(1/2) = 4•(1/2)² - 5•(1/2)

=> p(1/2) = 4•(1/4) - 5/2

=> p(1/2) = 1 - 5/2

=> p(1/2) = (2 - 5)/2

=> p(1/2) = -3/2