Question

x=root2 is a solution of a quadratic equation x2+kx-4=0.find the value of k

Answer 1

$P[ \sqrt{2} ]=2+k \sqrt{2} -4=k \sqrt{2} -2$=0
$k \sqrt{2} =2$
$k= \sqrt{2} /2$
hope this helps

Answer 2

Given that √2 is the zero of the polynomial
x² + kx - 4 = 0
⇒ (√2)² + k(√2) - 4 = 0
⇒ 2 + k·√2 - 4= 0
⇒ -2 + k·√2 = 0
⇒ k·√2 = 2
⇒ k = 2/√2
∴ k = √2