Question

if x=3 is one root of the aquodrotic equation x^2-2kx-6=0

Answer 1

x²-2kx-6=0
or 3²-2*k*3-6=0
or 9-6k-6=0
or -6k=-3
or k=1/2

Answer 2

x² - 2kx - 6 = 0

Solve x:

x = 3 is a root, therefore when x = 3, the equation is equal to 0

Sub x = 3 into the equation:

(3)² - 2k(3) - 6 = 0

Evaluate the brackets:

9 - 6k - 6 = 0

Combine like terms:

3 - 6k = 0

Add 6k to both sides:

3 = 6k

Switch sides:

6k = 3

Divide both sides by 6:

k = 3/6

Simplify:

k= 1/2

Answer: k = 1/2