Question

Check the values of x from the given options for which the value of polynomial $x^3-7x^2+14x-8$ becomes zero.

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

Answer: (A), (B), (D)

The correct options are
A

1

B

2

D

4

Substitute each of the options one by one in the polynomial.
On substituting x = 1
$=1^3-7(1{)}^2+14(1)-8$
$=1-7+14-8$
$=0$
On substituting x = 2
$=(2{)}^3-7(2{)}^2+14\left(2\right)-8$
$=8-28+28-8$
$=0$
On substituting x = 3
$(3{)}^3-7(3{)}^2+14\left(3\right)-8$
$=27-63+42-8$
$=69-71$
$=-2$
On substituting x = 4
$(4{)}^3-7(4{)}^2+14\left(4\right)-8$
$=64-112+56-8$
$=120–120$
$=0$
So the values 1, 2 and 4 make the polynomial $x^3-7x^2+14x-8$ become zero.