Question

if -1 ia a zero of the polynomial p(x)=ax³-x²+x+4 then find the value of a​

Answer 1

ANSWER:

• Value of 'a' is 2.

GIVEN:

• -1 is a zero of the polynomial p(x)=ax³-x²+x+4 .

TO FIND:

• Value of 'a'.

METHOD USED:

• Remainder theorem.

SOLUTION:

P(x) = ax³-x²+x+4

(-1) is the zero of the polynomial P(x). If we put (-1) in place of x then we will get the remainder 0.

=> P(-1) = a(-1)³-(-1)²+(-1)+4

=> -a-1-1+4 = 0

=> -a+2 = 0

=> -a = -2

=> a = 2

Value of 'a' is 2.

NOTE:

• This type of questions can be solved by using remainder theorem.
• Put the factor in the place of the variable and then equal the expression = 0.
• Then find the value of the variable asked.
• In this way we can solve this problem.