Question

4x^3+8x^2-x-2=0 then the value of (2x+3) is given by

Answer 1

4x³ + 8x² - x -2 = 0
4x²( x + 2 ) -1(x +2 ) = 0
(2x -1)(2x +1)(x +2 ) =0
here you see in factors of 4x³ + 8x² -x -2
has not (2x +3) , so, x = -3/2 putting get some value
put x = -3/2

=4(-3/2)³ +8(-3/2)²-(-3/2)-2

=4(-27/8)+8(9/4)+3/2-2

= -27/2 + 18 +3/2 -2

= -12 + 18 -2

= -14 + 18

= 4

Answer 2

Answer:

Step-by-step explanation:

Given: The polynomial 4x³ + 8x² - x - 2 = 0

To find: The value of 2x + 3 ?

Solution:

Now we have given the equation as:  

               4x³ + 8x² - x - 2 = 0

Taking common terms, we get:

               4x²(x + 2) - 1(x + 2) = 0

               (x + 2)(4x² - 1) = 0

               (x + 2)(2x - 1)(2x + 1) = 0

From this, the value of x is:

               x = -2 , 1/2 and -1/2

Putting this in 2x + 3, we get:

               x = -2, we get:

               2(-2)+3 = -4 + 3 = -1

                x = 1/2, we get:

               2(1/2) + 3 = 1 + 3 = 4

               x = -1/2, we get:

               2(-1/2) + 3 = - 1 + 3 = 2

Answer:

           So the values of 2x + 3 are -1, 2 and 4.