Question

value of k if (x-1 ) is factor of 2x²+ kx -5​

Answer 1

Answer:

3

I will tell you how it came.

Step-by-step explanation:

Here, x-1 is a factor of

$2 {x}^{2} + kx - 5$

So then x-1 must be equal to 0

$x - 1 = 0 \\ x = 1$

Substitute the value in the given quadratic expression.

$2 {x}^{2} + kx - 5 = 0$

$2 {(1)}^{2} + k(1) - 5 = 0$

$2 + k - 5 = 0$

$k - 3 = 0$

$k = 3$

If you like the process please comment.

Answer 2

Given:-

(x-1 ) is factor of 2x²+ kx -5.

To find:-

value of k

Solution:-

We know that if (x-1) is a factor then

• x-1=0

Thus x=1

$\\ \sf{:}\leadsto p(x)=2x^2+kx-5$

$\\ \sf{:}\leadsto p(1)=2(1)^2+k(1)-5$

$\\ \sf{:}\leadsto 2(1)+k-5=0$

$\\ \sf{:}\leadsto 2+k-5=0$

$\\ \sf{:}\leadsto k-3=0$

$\\ \sf{:}\leadsto k=3$