Question

if (x+1) is a factor of 2x^2+Kx then the value of k is________

​

Answer 1

Given:

• (x + 1) is factor of 2x² + kx

To find:

• The value of k

Solution:

p(x) = 2x² + kx

As we know by the factor theorem,

If (x + a) is a factor of p(x) , then p(-a) should be 0

here, p(-1) should be zero as 1 corresponds with a

p(x) = 2x² + kx

p(-1) = 2(-1)² + k(-1) = 0

From the equation, we can find the unknown k

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

= 2 - k = 0

= - k = -2

= k = 2

The value of k is 2

Verification:

Put 2 in place of k

p(x) = 2x² + 2x

By taking 2x as comman-

= 2x(x + 1)

we got the factors as 2x and (x + 1)

Hence, verified!